Heavy Ion Collisions at the LHC

Last Call for Predictions

Monday May 14th to Friday June 8th 2007

Talks during the Focus Week

Tuesday May 29th (TH Auditorium, 4-3-005)

9.00-9.10
Welcome

Introductory talk
9.10-10.00 (40+10)
Author: Wit Busza (MIT)
Title: Predictions for LHC PbPb collisions based on the extrapolation of lower energy data
Abstract: Many aspects of pp, pA and AA data obtained to date at a broad range of energies follow remarkably simple trends. I will review trends in multiplicity, pseudorapidity distributions, elliptic flow and attenuation of particles, from the lowest energies to RHIC energies. I will then use the observed trends to predict results for PbPb collisions at LHC. If the trends continue to the highest energies, a fundamental reason for this simplicity will need to be found if we are to understand the physics of heavy ion collisions.

Session 1. Multiplicities and multiplicity distributions
10.00-10.20 (16+4)
Author: Steffen A. Bass (Duke)
Title: Transport Analysis of Bulk QCD Matter at the LHC
Abstract: I will present predictions of the 3D-Hydro+UrQMD model for observables in the the soft sector for Pb+Pb collisions at LHC. Regarding observables, I shall focus on multiplicities and spectra - in addition I will present an analysis of the evolution, lifetime and freeze-out of the matter produced, both in terms of the deconfined as well as the confined phase.
10.20-10.40
(16+4)
Author: V. Topor Pop (McGill)
Title: Stopping power  and (Multi)Strangeness Production from SPS to LHC energies. HIJING/BbarB v2.0 predictions
Abstract: In the framework of HIJING/BbarB v2.0 model, the introduction of strong color field (SCF) has small effect on total charged particle production, and on stopping power, at RHIC energies. However, due to higher initial energy density (or temperature) we expect an increase of the mean value of the string tension, with increasing energy. Global observables such as as transverse momentum spectra and (pseudo)rapidity distributions of the charged hadrons produced in p+p and central(0-10%) Pb + Pb collisions at LHC energies, could help to quantify this increase. The energy dependence in asymptotic regime could help us to determine the properties of Junctions-anti-Junctions (JJbar) loops, within our model. The role played by JJbar loops at the LHC is investigated by analysing the specific stopping power observables and their energy dependence from SPS to LHC energies. In particular we will discuss the predictions of net-protons and net-baryons rapidity distributions, as well as the energy dependence of net-baryons per number of participants at mid-rapidity and mean rapidity loss. Strangeness and multi-strangeness particles production can be used to explore the initial transient field fluctuations in heavy ion collisions. We will emphasize the role played by Junction anti-Junction (JJbar) loops and strong color electric fields (SCF) in these collisions. Transient field fluctuations of SCF on the baryon production in central (0-10%) Pb+Pb collisions at \sqrt{s_NN} = 5.5 TeV will be discussed in the framework of HIJING/BbarB v2.0 model, looking in particular to the predicted evolution of nuclear modification factors (R_AA) from RHIC to LHC energies. In our presentation we will also discuss the baseline of elementary pp collisions at this energy.
10.40-11.00
(16+4)
Author: Sarah Porteboeuf (SUBATECH)
Title: EPOS Predictions at LHC Energies
Abstract: We present EPOS predictions for proton-proton scattering and for lead-lead collisions at different centralities at LHC energies. We focus  on soft physics and show particle spectra of identified particles. We  claim that collective affects are already important in proton-proton scattering.
11.00-11.30
Coffee break
11.30-11.50
(16+4)
Author: A. Capella (LPT Orsay)
Title: Multiplicities and elliptic flow at the LHC
Abstract: Using a final state interaction model which describes the data on these two observables at RHIC energy, we make predictions at the much higher energy of the Large Hadron Collider (LHC). All the parameters in the model, such as the pt-shift induced by the final state interaction and the cross-section of the latter are taken to be the same as at RHIC energy. The increase in the medium density between these two energies (by more than a factor 2) produces striking effects on these observables –such as an increase in the fixed pt suppression by more than an order of magnitude and an increase of the elliptic flow v2 by a factor close to 2 at low pT .
11.50-12.10 (16+4)
Author: Che-Ming Ko (Texas A&M)
Title: Heavy ion collisions at LHC in a multiphase transport model
Abstract: Using the AMPT model that includes scatterings in both initial partonic and final hadronic matters as well as the transition between these two phases of matter, we make predictions on the rapidity distributions and transverse momentum spectra of various hadrons and their elliptic flows.
12.10-12.30 (16+4)
Author: K.J. Eskola (Jyväskylä)
Title: Hadron multiplicities, pT-spectra and net-baryon number in central Pb+Pb collisions at the LHC
Abstract: We compute the initial energy density and net baryon number density in 5% most central Pb+Pb collisions at $\sqrt s=5.5$ TeV from pQCD + (final state) saturation, and describe the evolution of the produced system with boost-invariant transversely expanding hydrodynamics. In addition to the total multiplicity at midrapidity, we give predictions for the multiplicity of charged hadrons, pions, kaons and (anti)protons, for the total transverse energy and net-baryon number, as well as for the $p_T$-spectrum of charged hadrons, pions and kaons. We also predict the region of applicability of hydrodynamics by comparing these results with high-$p_T$ hadron spectra computed from pQCD and energy losses.
12.30-12.50
(16+4)
Author: Jose Guilherme Milhano(IST Lisbon)
Title: Multiplicity distributions in (pseudo) rapidity for Pb-Pb and p-Pb central collisions from a simple model
Abstract: We present predictions for multiplicity distributions in rapidity and pseudo-rapidity for Pb-Pb and p-Pb central collisions at the LHC. These predictions are based on the simple model introduced in hep-ph/0701215.
12.50-15.00
Lunch break
15.00-15.20
(16+4)
Author: Boris Z. Kopeliovich (Valparaíso)
Title: CGC and the Cronin effect at LHC
Abstract: The semi-hard scale generated by nonperturbative effects in the proton leads to a substantial reduction of the magnitude of CGC and Cronin enhancement at the energies of LHC.
15.20-15.40 (16+4)

Author: Edmond Iancu (Saclay)
Title: Pomeron loop effects on forward particle production in pp and pA collisions

15.40-16.00 (16+4)
Author: Kirill Tuchin (Iowa State)
Title: Forward hadron production in pA collisions
Abstract: I present a calculation of $\pi$, D and B mesons production at RHIC and LHC energies based upon a gluon saturation model.
16.00-16.20 (16+4)
Author: F. Gelis (CERN)
Title: Melting the CGC in pA and AA collisions at the LHC
Abstract: We discuss general features of multi-particle production at high energies and make predictions for inclusive final states in pA and AA collisions at the LHC.
16.20-16.40 (16+4)
Author: Erik Wessels (Vrije Universiteit Amsterdam)
Title:  Probing the Extended Geometric Scaling Region at LHC with polarized and unpolarized final states
Abstract: We present predictions for both pion production in p-Pb and p-p collisions and lambda polarization in p-Pb collisions, using the DHJ formalism.
16.40-17.10
Coffee break
17.10-17.30 (16+4)
Author: Carlos A. Salgado (Rome La Sapienza)
Title: Mutiplicities at the LHC from geometrical scaling
Abstract: We predict the multiplicity of charged particles at midrapidity based on geometrical scaling arguments. We also comment on the suppression of forward particles in pPb collisions.
17.30-17.50 (16+4)

Author: Jamal Jalilian-Marian (Baruch College, NY)
Title: Average pt of produced hadrons at LHC

17.50-18.10 (16+4)
Author: J. L Albacete (Ohio State)
Title: Multiplicities in Pb-Pb collisions at the LHC from running coupling evolution and RHIC data
18.10-18.30 (16+4)
Author: Michael Kozlov (Bielefeld)
Title: Total Gluon Shadowing due to Gluon Number Fluctuation Effects


Wednesday May 30th (TH Auditorium, 4-3-005)


Session 1. Multiplicities and multiplicity distributions (continued)
9.00-9.20 (16+4) Author: Johannes Ranft (Siegen)
Title: Inclusive distributions at the LHC as predicted from the DPMJET-III model with chain fusion
Abstract: DPMJET-III with chain fusion is used to calculate inclusive distributions of Pb-Pb and p-p collisions at LHC energies. We present p_(\perp) and rapidity distributions as well as scaled multiplicities at mid-rapidity as function of the collision energy and the number of participants.
9.20-9.35 (12+3)
Author: C. Pajares (Santiago de Compostela)
Title: Multiplicity distributions and percolation of strings
Abstract: In the framework of percolations of strings the rapidity distributions for central A-A collisions are shown for SPS, RHIC and LHC energies. The obtained value for LHC is lower than the one predicted for the rest of models but larger than the linear energy extrapolation from SPS and RHIC.

Session 2. Azimuthal asymmetries
9.35-9.55 (16+4)
Author: Ulrich Heinz (Ohio State)
Title: Hydrodynamics predictions on evolution of elliptic flow from RHIC to LHC
9.55-10.10 (12+3)
Author: Steffen A. Bass (Duke)
Title: Transport Analysis of Bulk QCD Matter at the LHC
Abstract:  In this second part of my presentation, I will show predictions for the generation of elliptic flow in the hybrid Hydro+Micro approach and discuss the possibility of an anomalous viscosity for QCD matter at LHC, leading to nearly ideal fluid behavior, even at very high temperatures and small coupling.
10.10-10.30 (16+4)
Author: Amir Rezaeian (Valparaíso)
Title: Perturbative QCD origin of azimuthal asymmetry
Abstract: The azimuthal elliptic flow observed in heavy ion collisions is usually associated with the properties of the medium created in final state. We show that part of the effect is due to multiple interaction of partons in nuclei at the initial stage of nuclear collisions. In our approach, the main driving force behind the elliptic flow originates from sensitivity of parton multiple intercations to the steep variation of the nuclear density at the edge of the nuclei throught dipole orientation. We also show that the inclusion of the suppresion effect of away-side jets in central collisions, significantly enhaces the elliptic flow.
10.30-11.00
Coffee break
11.00-11.20 (16+4)
Author: F. Becattini (Firenze)
Title: The effects of angular momentum conservation in heavy ion collisions at LHC
Abstract: In peripheral collisions at LHC, part of the large angular momentum of the colliding ions could be collectively transferred to the midrapidity interaction region giving rise to a spinning quark gluon plasma fireball. If the intrinsic angular momentum of the QGP fireball is large enough, there will be remarkable effects on several observables such as elliptic flow, transverse momentum spectra and hadron multiplicities. By taking advantage of a recent full calculation of the microcanonical and canonical ensembles of ideal relativistic quantum gases at fixed intrinsic angular momentum, we give quantitative predictions of those observables at LHC. In a statistically equilibrated spinning fireball, the predicted azimuthal momentum anisotropy is very similar to that generated by the pressure gradients in usual hydrodynamical approach; transverse momentum spectra are broadened; the chemical freeze-out temperatures determined by means of hadronic abundances could decrease with respect to central collisions. However, the most peculiar feature is an azimuthal anisotropic net polarization of produced hadrons, for which we provide momentum dependent quantitative predictions.
11.20-11.35 (12+3)
Author: A.M. Snigirev (SINP, MSU)
Title: Azimuthal anisotropy of jet quenching
Abstract: The azimuthal anisotropy of jet and high-p$_T$ hadron spectra due to partonic energy loss in the azimuthally non-symmetric volume of dense quark-gluon matter created in semi-central PbPb collisions at the LHC is analyzed in the frame of PYQUEN model.
11.35-11.55 (16+4)
Author: Marcus Bluhm (Dresden)
Title: Lattice QCD inspired equation of state: Impact on elliptic flow and transverse momentum spectra
Abstract: We discuss the equation of state of strongly interacting matter within a quasi-particle perspective. Our quasi-particle model is based on a chain of approximations starting from the QCD Lagrangian within the phi-functional approach to QCD. Successfully describing recent lattice QCD results on the thermodynamics of strongly interacting matter for zero and finite baryon chemical potential, we can extrapolate our results towards the chiral limit. This chirally extrapolated equation of state is used in the hydrodynamic investigation about transverse momentum spectra of primordial hadrons and about the elliptic flow at energies relevant for LHC. In particular, we discuss the influence of details of the equation of state in the transition region between hadronic phase and quark gluon plasma phase on these observables.
11.55-12.15 (16+4)
Author: Denes Molnar (Purdue)
Title: Elliptic flow results from parton transport
Abstract:  Results on elliptic flow will be presented from a covariant and causal transport framework. Dissipative effects are significant even in the "minimal viscosity" (most perfect fluid) limit.
12.15-14.00
Lunch break
14.00-15.00
(TH WEDNESDAY SEMINAR)
Author: Miklos Gyulassy (FIAS Frankfurt and Columbia)
Title: Im?Perfect Fluidity in Pb+Pb at LHC and the Critical p+Pb Missing Link
Abstract: The current claims for the near "Perfect Fluid" property of strongly coupled quark gluon plasmas (sQGP) discovered in 200 AGeV Au+Au at RHIC/BNL rest on the assumed control over the detailed phase space initial conditions of fields and partons produced in ultra-relativistic nuclear conditions. The Color Glass Condensate (CGC) initial conditions, which were expected theoretically to apply at both RHIC and LHC energies,  were recently found however to be incompatible with the observed elliptic flow. This raises the question of whether the celebrated viscosity/entropy=1/4 Pi lower bound derived via the AdS/CFT conjecture is actually reached in such reactions. Future data on Pb+Pb at 5.5 ATeV at the LHC/CERN will help to answer whether the sQGP is closer to a viscous fluid dual of a AdS5 "Grey Hole" or even a weakly coupled gas phase of QCD matter. The critical experimental control link, needed to deconvolute novel initial state physics from the bulk physics of ultra-dense deconfined quark gluon matter, will require the detailed measurements of all observables in p+Pb at LHC.
15.00-15.30
Coffee break
15.30-15.50 (16+4)
Author: Jean-Yves Ollitrault (Saclay)
Title: The centrality dependence of elliptic flow
Abstract: I show that the centrality and system-size dependence of elliptic flow measured at RHIC are fully described by a simple model based on eccentricity scaling and incomplete thermalization. I argue that the eccentricity from the Glauber model is too low, while the eccentricity from the color-glass condensate gives reasonable results. Tentative predictions for LHC are given.
15.50-16.05 (12+3) Author: Harri Niemi (Jyväskylä)
Title: Elliptic flow from pQCD + saturation + hydro
Abstract: We have previously predicted multiplicities and transverse momentum spectra of hadrons for the most central LHC Pb+Pb collisions at sqrt{s_{NN}}=5.5 TeV using initial state for hydrodynamic evolution from pQCD + final state saturation model. By considering binary collision and wounded nucleon profiles we extend these studies to non-central collisions, and predict the p_T dependence of minimum bias v_2 for pions at the LHC. For protons we also show how the p_T dependence of v_2 changes from RHIC to the LHC.

Session 4. Correlations at low transverse momentum
16.05-16.25 (16+4)
Author: Yu.M. Sinyukov (BITP, Kiev)
Title: Initial conditions and space-time scales in relativistic heavy ion collisions
Abstract: The space-time picture of the hadron emission versus initial energy density and transverse flow profiles will be analysed within hydro-kinetic model. The prediction for the interferometry radii in central nucleus-nucleus collisions at LHC energies and for averaged phase-space densities will be done.
16.25-16.40 (12+3)
Author: Ulrich Heinz (Ohio State)
Title: Hydrodynamics predictions on evolution of HBT radii from RHIC to LHC.
16.40-16.55 (12+3)
Author: Che-Ming Ko (Texas A&M)
Title: Heavy ion collisions at LHC in a multiphase transport model
Abstract: Using the AMPT model that includes scatterings in both initial partonic and final hadronic matters as well as the transition between these two phases of matter, we make predictions on two-pion correlation functions in ultra-relativistic heavy ion collisions at the Large Hadron Collider (LHC).
16.55-17.25
Coffee break
17.25-17.40 (12+3)
Author: Yu.M. Sinyukov (BITP, Kiev)
Title: Correlation radii by fast hadron freeze-out generator
Abstract: Correlation radii R(out), R(side) and R(long) in PbPb collisions at the LHC energies are analyzed in the frame of fast hadron freeze-out generator (FASTMC).
17.40-17.55 (12+3)
Author: Elena G. Ferreiro (Santiago de Compostela)
Title: Correlations at the LHC in the percolation approach

Session 5. Fluctuations
17.55-18.15 (16+4)
Author: K. Redlich (Wroclaw)
Title: Charge density fluctuations in the presence of spinodal instabilities
Abstract: Considering deviations from an idealized equilibrium picture of the first order chiral phase transition by including spinodal instabilities the properties and behavior of the charge density fluctuations are studied. It is shown that such instabilities generate divergent fluctuations of conserved charges along the isothermal spinodal lines appearing in the mixed phase. Consequently, divergent charge fluctuations are not only attributed to the critical end point but are also there across the first order phase transition. Thus, they could signal the first order phase transition expected in strongly interacting medium.
18.15-18.35 (16+4)
Author: F. Karsch (BNL)
Title: Baryon number and strangeness fluctuations
Abstract: We present results on fluctuations of net baryon number and strangeness in QCD at vanishing and non-vanishing baryon number density and temperature. These preliminary results are obtained from lattice calculations with almost physical up and down quark masses and a physical value for the strange quark mass. We show that at vanishing chemical potential, i.e. under conditions met at the LHC, quartic fluctuations of net baryon number and strangeness as well as the correlation of squared net baryon number and strangeness are large in a narrow temperature interval characterizing the transition region from the low to high temperature phase.  We also show that strangeness fluctuations are enhanced at non-zero baryon number density and are correlated to fluctuations of the latter. Nonetheless, in a dense medium with overall vanishing strangeness, as it is created in heavy ion collisions, strangeness fluctuations are significantly smaller than baryon number fluctuations.

Session 3. Hadronic flavor observables
18.35-18.50 (12+3)
Author: F. W. Bopp (Siegen)
Title: The Strangeness Dependence of Antibaryon to Baryon Production Ratios in Pb-Pb and p-p collision at LHC energies of the DPMJET-III Monte Carlo
Abstract: A sizable component of stopped baryons is predicted for Pb-Pb and p-p collisions at LHC energies. We present an analysis of the flavor dependencs of such ratios for the minimum bias or peripheral region at LHC energies within framework of the multichain Monte Carlo DPMJET-III.
18.50-19.10 (16+4) Author: Johann Rafelski (Arizona)
Title: Soft hadron ratios at the LHC
Abstract: The physics input governing soft hadron production at LHC-Ion comprises
a) dS/dy, the entropy content
b) ds/dy and s/S, strangeness content, also relative to entropy production
c) db/dy, nett baryon density
d) dE/dy, the energy content, and relative E/b
e) (primary) baryons to mesons ratio (b+bar b/ all mesons)
Many of these quantities are established by kinetic processes governing the initial state properties, and hadronization dynamics. Some of these we begin to understand from basic principles, e.g. strangeness production, others remain in the realm of simple approximations and extrapolations and we explore these within simple models, avoiding any mystification. Given this input data set,  hadron production is constrained by
a) Strangeness balance in a given window of rapidity
b) Net charge per net baryon ratio  Q/b=0.4 in given window of rapidity
c) Overall chemical equilibrium gamma_q=gamma_s=1, or allowing gamma_s to vary
d) Outflow dynamics: E/TS>1 for explosive break up, E/TS<1 for mixed phase


Thursday May 31th
(TH Auditorium, 4-3-005)


Session 3. Hadronic flavor observables (continued)
9.00-9.20 (16+4) Author: Peter Braun-Munzinger (GSI)
Title: Thermal model predictions of hadron ratios
Abstract: We present predictions of the thermal model for hadron ratios in central Pb+Pb collisions at LHC.
9.20-9.40 (16+4) Author: Sebastian Sapeta (CERN and Jagellonian University)
Title: Hadrochemistry of Jet quenching at the LHC
Abstract: We point out that jet quenching can leave signatures not only in the longitudinal and transverse jet energy and multiplicity distributions, but also in the hadrochemical composition of the jet fragments. For illustration, we use the MLLA+LPHD formalism of jet fragmentation, supplemented by medium-modified splitting functions. We discuss how jet hadrochemistry can be studied within the high-multiplicity environment of nucleus-nucleus collisions at the LHC.
9.40-10.00 (16+4)
Author: Su Houng Lee (Yonsei University, Seoul)
Title: Heavy exotic particle productions from HIC at LHC
Abstract: The chances of having an explicit exotic particle is much higher if there are several heavy quarks Possible candidates are ud \bar{c}\bar{c} type tetraquark, or uudd \bar{c} type heavy charmed pentaquark. I will give theoretical reasons why these explicit exotic particle are very likely to exist, and why LHC HIC are nice place to observe these states.
10.00-10.20 (16+4)
Author: Giorgio Torrieri (Frankfurt)
Title: Statistical model(s) predictions for fluctuations of ratios at the LHC
Abstract: We will use some of the statistical models currently on the market to calculate the expected fluctuation of particle ratios at LHC energies. Particular attention will be given to the scaling expectation of the fluctuations in terms of total multiplicity/system volume.
10.20-10.40 (16+4)
Author: Ingrid Kraus (GSI)
Title: Statistical model predictions in pp and PbPb collisions at LHC
10.40-11.10
Coffee break

Session 6. High transverse momentum observables and jets
11.10-11.30 (16+4) Author: Carsten Greiner (Frankfurt)
Title: Space-time evolution of QCD matter
Abstract: We investigate parton thermalization and energy loss of high pT jets in the course of space-time evolution of partons, simulated in a 3+1 dimensional pQCD inspired on-shell parton cascade. The contributions of elastic gg↔ gg as well as inelastic gg↔ggg pQCD processes to kinetic equilibration are manifested by the transport collision rates and calculated by choosing different initial conditions of partons produced in a central Au+Au collision at RHIC energy. We find that pQCD Bremsstrahlung processes are much more efficient for momentum isotropization compared to elastic scatterings. Also the way thermalization occurs is investigated and compared with the “Bottom-Up” scenario. The detailed balance of inelastic scatterings moderates the suggested scenario. We also calculate the nuclear modification factor RAA for high pT partons in the full course of the space-time evolution of parton matter.
11.30-11.50 (16+4)
Author: Boris Z. Kopeliovich (Valparaíso)
Title: Jet quenching: Alternative scenario
Abstract: An interpretation for suppression of high-pT hadrons in AA collisions, alternative to the energy loss scenario, is proposed. The effect is found to decouple from the properties of a dense medium. The mechanism naturally explains the observed strong suppressin of heavy flavored hadrons and pT-independent suppression of pions. Predictions for LHC are made.
11.50-12.10 (16+4)
Author: Igor Lokhtin (SINP MSU)
Title: High transverse momentum observables in PYQUEN model
Abstract: Nuclear modification factors for hard jets and high-pt hadrons, medium-modified jet fragmentation function (JFF) measured with leading hadrons and transverse momentum imbalance in dimuon tagged jet events are calculated in the frame of PYQUEN energy loss model. Significant suppression of leading hadrons and moderate suppression of the absolute jet rates (due to in-medium gluon bremsstrahlung out of jet cone) together with a significant softening of the JFF are predicted for PbPb collisions at the LHC. It is also shown that the expected medium-induced partonic energy loss can result in significant pT-imbalance between the muon pair and a leading particle in a jet for Z/gamma*+jet channel.
12.10-12.30 (16+4)
Author: C. Loizides (MIT)
Title: PQM prediction for RAA and RCP at midrapidity in Pb-Pb collisions
Abstract: The Parton Quenching Model (PQM) couples the BDMPS-SW quenching weights for radiative energy loss with a realistic description of the nucleus--nucleus collision geometry, based on the Glauber model.
We present the predictions for the nuclear modification factors, in Pb--Pb relative to pp collisions ($\RAA$) and in central relative to peripheral Pb--Pb collisions ($\RCP$), of the transverse momentum distributions of light-flavour hadrons at midrapidity.
12.30-12.50 (16+4)
Author: Jorge Casalderrey-Solana (LBL)
Title: Energy Dependence of the Jet Quenching Parameter \hat{q}
Abstract: We study the effect of evolution and saturation of the thermal gluon distribution function on the computation of the jet quenching parameter \hat{q}. For thermal particles, the saturation scale $Q^2_s$ is proportional to the Debye screening length. For hard probes, the evolution at small $x=Q^2_s/6ET$ leads to an energy dependence of $\hat{q}$. The experimental consequences for LHC are discussed.
12.50-14.20
Lunch break

Session 7. Quarkonium
14.20-14.40 (16+4)
Author: Peter Braun-Munzinger (GSI)
Title: Statistical hadronization model predictions for charmed hadrons
Abstract: We present predictions of the statistical hadronization model for charmed hadrons production in Pb+Pb collisions at LHC.
14.40-15.00 (16+4)
Author: Agnes Mocsy (BNL)
Title: Predictions for Quarkonium Properties Above Deconfinement
Abstract: Based on an approach that utilizes potential models combined with perturbative QCD we show that the temperature-dependence of quarkonium correlators from lattice QCD is reproduced, despite the fact that all quarkonium states, except the 1S bottomonium, are dissolved in the quark-gluon plasma. The spectral function is significantly enhanced over the one that corresponds to free quark propagation. Although the 1S bottomonium survives in the deconfined phase, this does not mean that the direct Upsilon production in heavy ion collisions is not suppressed. We discuss the properties of the Upsilon at high temperatures, and its implication for heavy ion phenomenology.
15.00-15.20 (16+4)

Author: R. L. Thews (Arizona)
Title: Predictions for rapidity and transverse momentum spectra of J/Psi formed by in-medium recombination in 5.5 TeV Pb-Pb at LHC
Abstract: We present calculations of J/Psi formation spectra which result from the combination of c and c-cbar quarks coming from c-cbar pairs produced in separate nucleon-nucleon interactions during Pb-Pb collisions at 5.5 TeV. The starting point is the corresponding spectra of charm quarks calculated at NLO in pQCD. We utilize a range of input nuclear parameters taken from extrapolation of results at RHIC energy, which will be constrained by future measurements in pp and pA interactions at LHC.

15.20-15.35 (12+3)
Author: E. G. Ferreiro (Santiago de Compostela)
Title: Fixed pt and J/psi suppression at the LHC
Abstract: Using a final state interaction model which describes the data on these two observables at RHIC energy, we make predictions at the much higher energy of the Large Hadron Collider (LHC). All the parameters in the model, such as the pt-shift induced by the final state interaction and the cross-section of the latter are taken to be the same as at RHIC energy. The increase in the medium density between these two energies (by more than a factor 2) produces striking effects on these observables –such as an increase in the fixed pt suppression by a factor 2 and an increase of the elliptic flow v2 by a factor close to 2 at low pT . The J/psi suppression is computed with sigco = 0.65 (the same value used at SPS and RHIC energies) and sigabs = 0 (ansatz consistent with the d-Au data at RHIC when shadowing is taken into account). The J/psi suppression increases by a factor 5.
15.35-15.55 (16+4)
Author: R. Vogt (Livermore)
Title: Baseline Predictions for Quarkonium Production and Suppression
Abstract:   I will present predictions of the rapidity and $p_T$ distributions of $J/\psi$ and $\Upsilon$ production in $pp$, $p$Pb and Pb+Pb collisions, including the effects of cold nuclear matter.  I will also discuss how the $\psi'/\psi$ and $\Upsilon'/\Upsilon$ ratios could be a sensitive measure of the characteristics of the quark-gluon plasma.
15.55-16.15 (16+4)
Author: Johann Rafelski (Arizona)
Title: Heavy flavor hadrons in statistical hadronization of strangeness-rich QGP
Abstract: We study b, c quark hadronization from QGP. We obtain the yields of charm and bottom flavored hadrons within the statistical hadronization model. The important novel feature of this study is that we take into account the high strangeness and entropy content of QGP, conserving strangeness and entropy yields at hadronization. In this talk the particular attention will be given to the modification of the expected yields of multi-charmed and strange hadrons including charmonium.
16.15-18.10
Coffee break; please note the CERN Colloquium by Franck Wilczek to be held in the Main Auditorium at 16.30.

Session 6. High transverse momentum observables and jets (continued)
18.10-18.30 (16+4) Author: Igor Dremin (LPI Moscow)
Title: Predictions and proposals for LHC on Cherenkov gluons
18.30-18.50 (16+4)

Author: Cristina Manuel (ICE-IEEC Barcelona)
Title: Exciting the quark-gluon plasma with a relativistic jet
Abstract: We discuss the properties of a system composed by a static plasma traversed by a jet of particles. Assuming that both the jet and the plasma can be described using a hydrodynamical approach, we find that unstable modes arise when the velocity of the jet is larger than the speed of the sound of the plasma and only modes with momenta smaller than a certain values are unstable. Moreover, for ultrarelativistic velocities of the jet the most unstable modes correspond to relative angles between the velocity of the jet and momentum of the collective mode $\sim \pi/4$. Our results suggest an alternative mechanism for the description of the jet quenching phenomenon, where the jet crossing the plasma loses energy exciting colored unstable modes. In LHC this effect should be seen with an enhanced production of hadrons for some specific values of their momenta and in certain directions of momenta space.

18.50-19.10 (16+4) Author: Barbara Betz (Frankfurt)
Title: Mach cones at LHC
Abstract: The energy loss of jets created in heavy ion collisions shows an anomalous behaviour of the angular distribution of particles created in the away-side jet due to the interaction of the jet with the medium. Recent three particle correlations confirm that a Mach cone is created. Ideal (3+1)d hydrodynamics is used to study the creation and propagation of such Mach cones under LHC conditions.
19.10-19.30 (16+4) Author: Björn Bäuchle (Bergen)
Title: Machcones at LHC via MACE
Abstract: MACE, a new approach to propagate sound-like perturbations as created by a jet moving with supersonic velocity through the medium present in heavy-ion reactions is used to calculate two-particle and three-particle correlations at central Pb+Pb-Collisions at LHC. We do not postulate the shape of an evolving mach front, but create it dynamically by considering elementary waves created in constant time intervals. Backreaction of the sound propagation onto the medium is neglected.



Friday June 1st (TH Auditorium, 4-3-005)


Session 6. High transverse momentum observables and jets (continued)
9.00-9.20 (16+4)

Author: Xin-Nian Wang (LBNL)
Title: Single and dihadron suppression at RHIC and LHC

9.20-9.40 (16+4)
Author: Simon Wicks (Columbia)
Title: Perturbative jet energy loss mechanisms: Learning from RHIC, extrapolating to LHC
Abstract: In many recent papers, collisional energy loss has been found to be of the same order as radiative energy loss for parameters applicable to the QGP at RHIC. As the temperature and jet energy dependence of collisional energy loss differs from that of radiative loss, the interpretation of the results at RHIC affects our extrapolation to predictions for the LHC. We present results from a collisional plus radiative model, combining DGLV radiative loss with HTL-modified collisional loss, including the poissonian spectrum of fluctuations for small numbers of collisions and gluons emitted. Currently unavailable at RHIC, the three simultaneous measurements of pion-producing jets, charm jets and bottom quark jets at LHC will provide strong constraints to the energy loss mechanisms.
9.40-10.00 (16+4)
Author: Hans J. Pirner (Heidelberg)
Title: Jet evolution in the quark gluon plasma
Abstract: Jet evolution is calculated in the leading log approximation. We solve the evolution equation for the branching of gluons in vacuum, using a triple differential fragmentation function D(x;Q2; p2). Adding an extra scattering term for evolution in the quark gluon plasma we investigate the in uence of the temperature of the plasma on the differential cross section of partons dN/d ln(1/x) in a jet of virtuality Q2 = (90 GeV)2. Due to scattering on the gluons in the plasma the multiplicity increases, the centroid of the distribution shifts to smaller x-values and the width narrows.
10.00-10.20 (16+4)

Author: Ivan Vitev (Los Alamos)
Title: GLV predictions for light hadron production and suppression at the LHC
Abstract: Simulations of neutral pion quenching in Pb+Pb reactions at s^1/2 = 5.5 ATeV at the LHC are presented to high transverse momentum pT . At low and moderate pT , we study the contribution of medium-induced gluon bremsstrahlung to single inclusive hadron production. At the LHC, the redistribution of the lost energy is shown to play a critical role in yielding nuclear suppression that does not violate the participant scaling limit. Energy loss in cold nuclear matter prior to the formation of the QGP is also investigated and shown to have effect on particle suppression as large as doubling the parton rapidity density.

10.20-10.40 (16+4)
Author: A. Majumder (Duke)
Title: High p_T single inclusive suppression and intra-jet correlations at the LHC
Abstract:  We present predictions for the R_{AA} of charged pions up to very high transverse momentum at \sqrt{s} = 5.5 TeV in the higher twist formalism. Predictions are made for various different centralities of the collision and for different choices of the initial transport parameter qhat. Results for different  medium parameterizations are presented, from a wounded nucleon model to that from a 3-D hydro-dynamically expanding  medium. Predictions are also made for the near side associated hadron yield as a function of associated momentum and centrality.
10.40-11.10
Coffee break
11.10-11.30 (16+4)
Author: Thorsten Renk (Jyväskylä)
Title: Charged hadron R_AA as a function of p_T from radiative energy loss within a hydrodynamical soft medium
Abstract: The idea of describing the initial state of A-A collisions using pQCD and saturation, followed by a hydrodynamics evolution of soft matter has not only given a good description of bulk matter dynamics at RHIC but has also predictive power for LHC. Using the framework for the soft medium background, we study hard processes embedded into the soft dynamics within a radiative energy loss picture calibrated at current RHIC data. Quite generally, as long as hadronization takes place outside the medium, the energy loss can be cast into the form of a geometry-averaged probability P(Delta E, E) for a parton of initial energy E to lose the amout Delta E to the medium. Any properties of the medium are then encoded in this distribution. We demonstrate that P(Delta E,E), if approximately independent of E as indicated by current RHIC data, can be studied by observing a rise of the nuclear suppression R_AA with p_T and show our current expectations for the pattern of this rise.
11.30-11.50 (16+4)
Author: William Horowitz (Columbia)
Title: pQCD Predictions vs. a String Theory Heavy Quark Energy Loss Signal at the LHC
Abstract: pQCD makes very strong predictions for the momentum dependence of heavy quark energy loss. Deviations from this would be a clear signal of new physics, and we provide several possibilities of a different dependence given by string theory calculations. The PID and momentum reach of the LHC will permit an observation of a discrepancy within the first year of running.
11.50-12.10 (16+4) Author: C. Pajares (Santiago de Compostela)
Title: Universal behaviour of transverse momentum distributions of mesons and baryons in the framework of percolation of strings
12.10-12.30 (16+4)
Author: D. Antonov (Heidelberg)
Title: Jet quenching parameter $\hat q$ from Wilson loops in a thermal  environment
Abstract:  The gluon jet quenching parameter is calculated in SU(3) quenched QCD  within the stochastic vacuum model. At the LHC-relevant temperatures, it is defined by the gluon condensate and the vacuum correlation length. Numerically, when the temperature varies from $T_c=270{\,}{\rm MeV}$ to the inverse vacuum correlation length $\mu=894{\,}{\rm MeV}$, the jet quenching parameter rises from zero to $1.1{\,}{\rm GeV^2}/{\rm fm}$.
12.30-12.50 (16+4)
Author: Gergely G. Barnafoldi (RMKI Budapest)
Title: Particle Ratios at High-$p_T$ at LHC energies
Abstract: Hadron production has been calculated in a pQCD improved parton model for pp, dA and heavy ion collisions. We applied KKP and AKK fragmentation functions. Hadron ratios --- measurable by the ALICE experiment --- have been investigated.  Our jet fragmentation study shows, that hadron ratios at high-pT depend on quark contribution mostly and less on the gluonic one. This finding can be seen in jet-energy loss calculations, also. We display the suppression pattern on different hadron ratios in PbPb collisions at LHC energies. Calculations in dPb collisions have been performed and the results are presented.
12.50-15.00
Lunch break

Session 7. Quarkonium (continued)
15.00-15.20 (16+4)
Author: M. V. Machado (UNIPAMPA, Brazil)
Title: Quarkonium production in coherent AA and pA collisions and small-x physics
Abstract: In this contribution we study the photoproduction of Quarkonium in coherent and incoherent nucleus-nucleus (AA) and proton-nucleus (pA) interactions at LHC. The integrated cross sections and rapidity distributions are estimated using the Color Glass Condensate (CGC) formalism, which takes into acount the parton saturation effects at high energies. A comparison with the QCD linear dynamics predictions is also presented.
15.20-15.40 (16+4)
Author: K. Tywoniuk (Oslo)
Title: Heavy-quark production from Glauber-Gribov theory at LHC
Abstract: We present predictions for heavy-quark production for proton-lead collisions at LHC energy 5.5 TeV from Glauber-Gribov theory of nuclear shadowing. We have also made predictions for baseline cold-matter (in other words inital-state) nuclear effects in lead-lead collisions at the same energy that has to be taken into account to understand properly final-state effects.
15.40-16.00 (16+4)

Author: Ivan Schmidt (Valparaíso)
Title: Diffractive Heavy Flavor Production
Abstract: Diffractive production of heavy flavors at RHIC and LHC energies is calculated. Novel leading twist mechanisms are proposed, which involve both short and long transverse distances inside the incoming hadron. The diffractive cross section turns out to be sensitive to the primordial transverse momenta of projectile gluons, rather than to the hadronic size.

16.00-16.15 (12+3)

Author: Carlos A. Salgado (Rome La Sapienza)
Title: Nuclear suppression for heavy flavors in PbPb collisions at the LHC
Abstract: We predict the nuclear suppression factors for D and B mesons, and for electrons from their semi-leptonic decays, in PbPb collisions at the LHC. The results are obtained supplementing a perturbative QCD calculation through FONLL with radiative energy loss.

16.15-16.30 (12+3)
Author: Andrea Dainese (Padova)
Title: RAA(pt) and RCP(pt) of single muons from heavy quark and vector boson decays at the LHC
16.30-17.00 Coffee break
17.00-17.15 (12+3)
Author: Igor Lokhtin (SINP MSU)
Title: High-mass dimuon and secondary charmonium spectra
Abstract: Medium-modified production of high-mass dimuons (from correlated semileptonic B-Bbar decay) and secondary charmonia (from single B-meson decay) in PbPb collisions at the LHC is simulated in the frame of PYQUEN model. A significant modification of high-mass dimuon and secondary J/Psi spectra due to bottom quark rescattering and energy loss in quark-gluon plasma is predicted.
17.15-17.35 (16+4)
Author: Hendrik van Hees (Texas A&M)
Title: Heavy-Quark Kinetics in the QGP at LHC
Abstract: A surprisingly large suppression and elliptic flow in non-photonic electron spectra (associated with the decay of open-charm (D) and open-bottom (B) mesons) in Au-Au collisions at RHIC have challenged the perturbative energy-loss picture. The data can be better described when implementing nonperturbative (elastic) heavy-quark interactions mediated by heavy-light resonances in the Quark-Gluon Plasma, which are operative up to temperatures ~2T_c, as suggested by lattice QCD. In this talk, we apply our approach to heavy-quark observables at LHC where the initial temperatures are expected to exceed 2T_c. We employ relativistic Langevin simulations to evaluate the thermalization process of heavy quarks in the QGP using both perturbative and nonperturbative rescattering in the QGP. At T_c, the heavy quark spectra are hadronized in a combined quark-coalescence/fragmentation model, and predictions are provided for D, B and decay-electron spectra. The predictions are put into context with RHIC results.
17.35-17.55 (16+4)

Author: Magdalena Djordjevic (Ohio State)
Title: Effect of dynamical QCD medium on radiative heavy quark energy loss
Abstract: The computation of radiative energy loss in a dynamically screened QCD medium is a key ingredient for obtaining reliable predictions for jet quenching in ultra-relativistic heavy ion collisions. We calculate, to first order in the number of scattering centers, the energy loss of a heavy quark traveling through an infinite and time-independent QCD medium consisting of dynamical constituents. We show that the result for a dynamical medium is almost twice that obtained previously for a medium consisting of randomly distributed static scattering centers. A quantitative description of jet suppression in RHIC and LHC experiments thus must correctly account for the dynamics of the medium's constituents.


Session 8. Leptonic probes and photons
17.55-18.15 (16+4) Author: D. d'Enterria (CERN)
Title: Photon and identified hadron spectra in Pb-Pb at 5.5 TeV: hydro+pQCD predictions
Abstract: We will present the expected pT-differential spectra of direct  photons and identified charged hadrons (pi, k, p) produced in various centrality classes in Pb-Pb reactions at \sqrt(s_NN) = 5.5 TeV as obtained with a 2D+1 hydrodynamical model with realistic initial conditions for the produced medium at LHC energies for the "soft" particle production, and Next-to-Leading-Order perturbative QCD calculations (including final-state quenching) for the perturbative contributions.
18.15-18.35 (16+4)
Author: Rainer J. Fries (Texas A&M)
Title: Photons and Dileptons at LHC
Abstract: We present our predictions for photon and dilepton spectra for Pb+Pb collisions at LHC, taking into account all relevant sources. In particular, we discuss the importance of emission from jets going through the hot and dense medium.
18.35-18.55 (16+4)
Author: Francois Arleo (CERN)
Title: Prompt photon production in p-p, p-A and A-A collisions at LHC
Abstract: The transverse momentum spectrum of prompt photons is first computed in QCD at NLO in p-p collisions at sqrt(s)=5.5 and 14 TeV. I will then show how the suppression of isolated prompt photons in p-A collisions at LHC provides stringent constraints on the amount of gluon nuclear shadowing at small x. Possible parton energy loss effects on fragmentation photons in A-A collisions is also discussed. Finally, the momentum imbalance distribution between a prompt photon and a leading hadron is presented in p-p and A-A collisions.



Saturday June 2nd (TH Auditorium, 4-3-005)


Session 8. Leptonic probes and photons (continued)
10.30-10.50 (16+4) Author: Hendrik van Hees (Texas A&M)
Title: Dileptons at LHC
Abstract: Low-mass dilepton spectra in heavy-ion collisions at the CERN-SPS have provided direct evidence for strong modifications of the rho meson in hot and dense strongly interacting matter. In addition, thermal radiation at intermediate mass (1GeV<3GeV) promises to deduce the temperature in the earliest phases of the collision. In this talk we predict diletpon spectra in Pb-Pb collisions at LHC. We evaluate thermal radition from both QGP and hadronic phases, as well as Drell-Yan annihilation and open-charm decays. The low-mass region is dominated by in-medium decays of the light vector mesons rho, omega and phi, whose in-medium spectral functions are calculated using hadronic many-body theory, resulting in a substantial broadening of their line shapes. The role of net vs. total baryon density, as well as possible ramifications annihilation and open-charm decays. The low-mass region is dominated by in-medium decays of the light vector mesons rho, omega and phi, whose in-medium spectral functions are calculated using hadronic many-body theory, resulting in a substantial broadening of their line shapes. The role of net vs. total baryon density, as well as possible ramifications for the nature of chiral symmetry restoration, are discussed. At intermediate masses, radiation from the QGP takes over, which, however, has to compete with Drell-Yan and open-charm contributions.
10.50-11.10 (16+4)
Author: A. H. Rezaeian (Valparaíso)
Title: Direct photons at LHC

Session 4. Correlations at low transverse momentum (continued)
11.10-11.25 (12+3)
Author: J. Dias de Deus (IST Lisbon)
Title: Prediction for Forward-Backward (F-B) rapidity correlations in a two step scenario
Abstract: We argue that in models where particles are produced in two steps, formation first of longitudinal sources (glasma and string models), followed by local emission, the Forward-Backward correlation parameter $b$ must have the structure \[ b={\langle n_B\rangle /\langle n_F\rangle \over 1+K/\langle n_F\rangle } \ , \] where $\langle n_B\rangle (\langle n_F\rangle )$ is the multiplicity in the backward (forward) rapidity window and $1/K$ is the (centrality and energy dependent) normalized variance of the number of sources.
11.25-11.55 Coffee break

Session 9. Others
11.55-12.15 (16+4)

Author: Horst Stöcker (Frankfurt)
Title: Early black hole signals at the LHC
Abstract: We review strategies for identifying speculative mini black hole events (due to large extra dimensions) at the LHC. A short survey on estimates for production cross sections, Hawking radiation, di-jet suppression and multi- mono-jet emission is made. We further make more detailed analysis of the conjecture of existence of stable black hole remnants. As concluding remark is mentioned that Mach cones are also to be expected from the high energetic Hawking jets propagating through the medium.

12.15-12.35 (16+4)

Author: Ina Sarcevic (Arizona)
Title: Hadrons as Signature of Black Hole Production is Heavy Ion Collisions at the LHC
Abstract: We propose a novel way to detect black hole production at the LHC by measuring the charged hadron spectra in Pb+Pb collisions.  We compute the charged hadron spectra from the decay of black hole and show that it dominates at transverse momenta $p_T\aprge 30-100$ GeV compared to usual QCD processes and black hole production.  In models with several large extra dimensions and fundamental Planck scale of the order of 1 TeV, LHC is expected to be a black hole factory. We show that a measurement of the charged hadron spectra probes Planck scales up to 5~TeV for any number of extra dimensions. Black holes can also be created in $pp$ collisions at the LHC, but the rates in $Pb+Pb$ collisions are higher due to an enhancement given by the number of binary collisions.  We discuss the interactions of the partons produced in the decay of the black hole with the quarks and gluons around it.  The energy loss is expected to be small at high transverse momentum, but at $p_T$ below 10 GeV the effect in the QCD spectrum is significant.  There is a possibility to have enhanced particle yield around $p_T \sim 10$ GeV/c, because the hadron spectra is much steeper than that of the QCD spectra and feedback from the emitted gluons could be non-negligible.  If this is the case, the black hole signal could be detected in the lower $p_T$ region.  We discuss the possible absorption of the particles surrounding the black hole which, in principle, would affect the decay of the black hole.

12.35-12.55  (16+4)

Author: A.M. Snigirev (SINP MSU)
Title: Alignment as a result from QCD jet production or new still unknown physics at the LHC?
Abstract: We would like to draw attention of the high-energy physics community to very important experimental results indicating our lack of understanding of features of hadron interactions at super-high energies and the necessity of improving recent theories.

12.55-13.10
Closing