Prof.
Misha Stephanov
(UIC)
12/08/2012, 09:00
Oral Presentation
Javier Lopez Albacete
(IPhT-CEA)
12/08/2012, 10:30
Oral Presentation
Paul Sorensen
(BNL)
12/08/2012, 11:30
Oral Presentation
Hannah Petersen
12/08/2012, 13:00
Oral Presentation
Dr
Bjoern Schenke
(Brookhaven National Lab)
12/08/2012, 13:30
Oral Presentation
Mike Lisa
(Ohio State University (US))
12/08/2012, 13:40
Oral Presentation
Yen-Jie Lee
(CERN)
12/08/2012, 14:30
Oral Presentation
Paul Chesler
(MIT)
12/08/2012, 14:35
Oral Presentation
Bill Zajc
(Columbia University)
12/08/2012, 15:30
Oral Presentation
Nestor Armesto Perez
(Universidade de Santiago de Compostela (ES))
12/08/2012, 17:15
Oral Presentation
13/08/2012, 08:30
Bart Gordon
13/08/2012, 09:00
Urs Wiedemann
(CERN)
13/08/2012, 09:30
Oral Presentation
Takao Sakaguchi
(BNL)
13/08/2012, 10:45
Oral Presentation
Xin Dong
(LBNL)
13/08/2012, 11:10
Oral Presentation
Karel Safarik
(CERN)
13/08/2012, 11:35
Oral Presentation
Barbara Krystyna Wosiek
(Polish Academy of Sciences (PL))
13/08/2012, 12:00
Oral Presentation
Gunther Roland
(Massachusetts Inst. of Technology (US))
13/08/2012, 12:25
Oral Presentation
Adrian Dumitru
(Baruch College (City University of New York))
13/08/2012, 14:15
Kevin Dusling
13/08/2012, 14:40
Matthew Wysocki
(University of Colorado at Boulder)
13/08/2012, 15:05
Dr
Jean-Yves Ollitrault
(CNRS)
13/08/2012, 15:30
Daniel Cebra
(UC Davis)
13/08/2012, 15:55
Sergey Voloshin
(Wayne State University (US))
13/08/2012, 16:50
Stephen James Sanders
(University of Kansas (US))
13/08/2012, 17:15
This talk will present an overview of collective flow phenomena and dihadron correlations from the CMS experiment at the LHC in pp and PbPb collisions. Fourier components of the anisotropic azimuthal distribution, ranging from the second to the sixth component, are obtained using different analysis techniques, which have different sensitivities to non-flow and flow fluctuation effects....
Adam Trzupek
(Polish Academy of Sciences (PL))
13/08/2012, 17:40
Huichao Song
13/08/2012, 18:05
Guilherme Teixeira De Almeida Milhano
(Instituto Superior Tecnico (PT))
14/08/2012, 08:30
Oral Presentation
Martin Spousta
(Columbia University and Charles University)
14/08/2012, 08:50
Oral Presentation
Dr
Andreas Morsch
(CERN)
14/08/2012, 09:10
Oral Presentation
Dr
Gabor Veres
(CERN)
14/08/2012, 09:30
Oral Presentation
Michael McCumber
(University of Colorado)
14/08/2012, 09:50
Oral Presentation
Marian Ivanov
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
14/08/2012, 10:10
Oral Presentation
Wei Xie
(Purdue University (US))
14/08/2012, 11:15
Oral Presentation
Prof.
Marzia Rosati
(Iowa State University)
14/08/2012, 11:35
Oral Presentation
Zaida Conesa Del Valle
(CERN)
14/08/2012, 11:55
Oral Presentation
William Horowitz
(University of Cape Town)
14/08/2012, 12:15
Oral Presentation
Takafumi for the PHENIX Collaboration Niida
(University of Tsukuba)
14/08/2012, 14:15
Oral Presentation
The HBT measurement provides the information on the space-time evolution of particle emitting source in relativistic heavy ion collisions. Azimuthal component of 3D HBT radii relative to event plane gives us the information of the source shape at freeze-out. It also provides the information of the system evolution by comparing with the initial source shape.
The recent measurement of higher...
Dong Ho Moon
(Korea University (KR))
14/08/2012, 14:15
Heavy flavor and quarkonium production
Oral Presentation
CMS has measured the nuclear modification factors of prompt J/psi in PbPb collisions at sqrt(sNN) = 2.76 TeV. For prompt J/psi with relatively high pT (6.5 < pT < 30 GeV/c), a strong, centrality-dependent suppression is observed in PbPb collisions, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. During the 2011 data taking period the data...
Edward Shuryak
(stony brook university)
14/08/2012, 14:15
Oral Presentation
Large energy deposition from LHC quenching jets restarted interest
to shock formation. Shocks also have theoretical significance as
the simplest out-of-equilibrium setting without time dependence.
While weak shocks have small gradients and can be
treated hydrodynamically in the Navier-Stokes (NS) approximation,
the ones without a small parameter (strong shocks) needs other methods.
Two...
Yue Shi Lai
(Massachusetts Inst. of Technology (US))
14/08/2012, 14:15
The first measurement of the transverse momentum (pT) imbalance of isolated-photon+jet pairs in relativistic heavy ion collisions is reported. The analysis uses data from PbPb collisions at a center-of-mass energy of 2.76 TeV per nucleon pair and corresponding to an integrated luminosity of 150/ub recorded by the CMS experiment at the LHC in 2011. For events containing an isolated photon with...
Neha Shah
(UCLA)
,
neha shah
(University of California Los Angeles)
14/08/2012, 14:35
Oral Presentation
Measurement of correlations of pair of particles with small relative momenta provides insight into geometry and lifetime of particle emitting source in relativistic heavy ion collisions.
Kaon femtoscopy extends the range of pair transverse mass covered and provides a sample less affected by decay resonances as compared to pions. The correlation functions of non-identical particles in the...
Roberta Arnaldi
(Universita e INFN (IT))
14/08/2012, 14:35
Oral Presentation
ALICE is the LHC experiment dedicated to the study of heavy ion collisions. The main purpose of ALICE is to investigate the properties of a new state of deconfined nuclear matter, the Quark Gluon Plasma. Quarkonium measurements will play a crucial role in this investigation. In particular, the sequential suppression of the quarkonium states by color screening has long being suggested as a...
YI GU
(D)
14/08/2012, 14:35
Oral Presentation
Collective flow measurements continue to play an important role in ongoing efforts to map out the temperature dependence of the transport coefficient $\frac{\eta}{s}(T)$, for the strongly interacting matter produced in heavy ion collisions at RHIC. Recently, PHENIX has performed a detailed set of measurements of the higher-order flow coefficients ($v_{n}$ for n=2,3,4), for both inclusive and...
Zvi Citron
(Weizmann Institute of Science (IL))
14/08/2012, 14:35
Oral Presentation
The correlations of jets with neutral bosons is a particularly powerful tool to probe the underlying physics of jet quenching. To gain insight into the physics of this process we can study Z-jet and gamma-jet correlations. Because the Z and photons do not directly couple to the strong force, in a jet+boson event the unmodified bosons allow us to access the modification of the opposite side...
Yadav Pandit
(Kent State University)
14/08/2012, 14:55
Global and collective dynamics
Oral Presentation
A primary goal of the RHIC Beam Energy Scan (BES) is to search for evidence of a transition
between a hadron gas and a Quark Gluon Plasma. The dependence of $v_{1}$ and higher flow
harmonics on system size and beam energy may be sensitive to the degrees of
freedom in the system, as a consequence of early pressure gradients and a potential softening in
the equation of state. In this talk,...
Peter Petreczky
(BNL)
14/08/2012, 14:55
Oral Presentation
We calculate different types of Wilson loops of temporal size
t < 1/T at non-zero temperatures on the lattice using Highly Improved
Staggered Quark (HISQ) action and temporal extent Nt=8 and 12.
Unlike other static correlators which go around the periodic
boundary these Wilson loops are not related to the free energy
of static quark anti-quark pair. Therefore from the analysis of...
Maciej Pawel Szymanski
(Warsaw University of Technology (PL))
14/08/2012, 14:55
Oral Presentation
In heavy-ion collisions produced at the LHC two-particle correlations
of mesons and baryons carry important information about the emitting
source. At low relative momentum femtoscopic correlations arise, which
are sensitive to the homogeneity lengths of the system. Hydrodynamic
models predict that these will decrease with increasing transverse
mass of the pair. Such decrease is...
Justin Edward Frantz
(Ohio University (US))
14/08/2012, 14:55
Oral Presentation
A variety of heavy-ion data from RHIC and recently also from the LHC on hard direct photon production testifies that this "white" probe of the densely colored QGP continues to lend new insights to understanding jet suppression and energy loss. It also allows first comparisons between RHIC and LHC energies for the behavior of energy loss, for example whether jet fragmentation function is...
Chun Shen
(Ohio State University)
14/08/2012, 15:15
Global and collective dynamics
Oral Presentation
We present a systematic study on the evolution of hadron spectra and their azimuthal anisotropy from the lowest collision energy studied at the Relativistic Heavy Ion Collider (RHIC), √s = 7.7A GeV, to the highest energy reachable at the Large Hadron Collider (LHC), √s = 5500A GeV [1]. As the collision energy increases, the resulting increases of the initial temperature, and fireball lifetime,...
Nicolas Arbor
(Centre National de la Recherche Scientifique (FR))
14/08/2012, 15:15
Oral Presentation
Gamma-hadron correlations measured in heavy-ion collisions produced at the LHC allow to investigate medium induced jet modifications in a transverse momentum (p_t) range below 50 GeV/c, where jet reconstruction is challenging because of the relatively large contribution from the underlying event. At high p_t direct photons, produced in Compton and annihilation QCD leading order processes, are...
Darren McGlinchey
(F)
14/08/2012, 15:15
Oral Presentation
The idea of using heavy quarkonia production as a direct probe of the screening length in the quark gluon plasma (QGP) has been around for over two decades. Suppression of quarkonia production in heavy ion collisions has been measured at the SPS, RHIC, and the LHC, including new measurements of $\Upsilon(1S+2S+3S)$ production in Au+Au collisions by PHENIX. However, a full understanding of...
Rylan Towne Conway
(University of California Davis (US))
14/08/2012, 15:15
Correlations and fluctuations
Oral Presentation
New precision measurements of dihadron correlations triggered by a very high-pT particle in 2.76 TeV PbPb collisions over a broad range of pseudorapidity and the full range of azimuthal angle will be presented. Utilizing a novel and unique high-pT single-track high-level trigger, the analysis explores the full 2011 PbPb data set corresponding to an integrated luminosity of 150/ub collected by...
Alexandru Florin Dobrin
(Wayne State University (US))
14/08/2012, 15:35
Correlations and fluctuations
Oral Presentation
Strong fluctuations of the anisotropic flow and the large acceptance of the ALICE detector allow an efficient selection of the events corresponding to a specific initial geometry. This opens many new possibilities to study the properties of the system created in ultra-relativistic nuclear collisions. In this talk, using the Pb-Pb collisions at $\sqrt{s_{NN}} = 2.76$~TeV data, we demonstrate...
Mr
Li Yan
(Stony Brook University)
14/08/2012, 15:35
Oral Presentation
The particle spectrum from RHIC and LHC can be decomposed into harmonic series that defines the dipolar flow $v_1$, the elliptic flow $v_2$, the triangular flow $v_3$, and $v_4$, and $v_5$ etc. To understand the origin of higher order harmonics, we extend the linear response formalism for anisotropic flow to include the non-linear response which results from the interactions between the lowest...
Barbara Trzeciak
(Warsaw University of Technology)
14/08/2012, 15:35
Oral Presentation
The suppression of quarkonia production in high energy nuclear collisions relative to proton-proton collisions, due to the Debye screening of the quark-antiquark potential, was proposed as a signature of the formation of Quark-Gluon Plasma. However, there are other effects that may affect the observed quarkonia production, such as cold nuclear matter effects, final state nuclear absorption and...
225.
Azimuthal anisotropy of charged hadrons at very high pT in PbPb collisions at 2.76 TeV with CMS
Victoria Zhukova
(University of Kansas (US))
14/08/2012, 15:55
Measurements of the azimuthal anisotropy of charged hadrons are presented for PbPb collisions at 2.76 TeV over an extended transverse momentum range up to approximately 60 GeV/c. The data were collected with the CMS detector at the LHC. Utilizing a novel and unique high-pT single-track high-level trigger, the analysis explores the full 2011 PbPb data set corresponding to an integrated...
Ralf Rapp
(Texas A&M University)
14/08/2012, 15:55
Heavy flavor and quarkonium production
Oral Presentation
We employ a kinetic rate-equation approach in a thermally expanding medium to compute the suppression and regeneration of quarkonia in heavy-ion collisions [1]. The in-medium properties of quarkonia figuring into the rate equation (widths, binding energies and heavy-quark masses) are constrained by euclidean correlators from lattice QCD. Input cross sections for heavy quarks and quarkonia, as...
Gabriel Denicol
(Frankfurt University)
14/08/2012, 15:55
Global and collective dynamics
Oral Presentation
We present a general derivation of relativistic fluid dynamics from the relativistic Boltzmann equation using the method of moments [1]. The main difference between our approach and the traditional 14-moment approximation is that we do not close the fluid-dynamical equations of motion by truncating the expansion of the single-particle momentum distribution function. Instead, we keep all the...
Guillermo Breto Rangel
(University of California Davis (US))
14/08/2012, 16:45
Heavy flavor and quarkonium production
Oral Presentation
The three Y states (1S, 2S, 3S) can be separated using the CMS experimental apparatus via their dimuon decays in both pp and heavy-ion collisions. A suppression of the Y(1S) and Y(2S) mesons is observed in PbPb collisions at sqrt(sNN) = 2.76 TeV, compared to the yield in pp collisions scaled by the number of inelastic nucleon-nucleon collisions. Furthermore, a suppression of the excited Y...
Dominik Karol Derendarz
(Polish Academy of Sciences (PL))
14/08/2012, 16:45
Oral Presentation
Anisotropy coefficients v_n are important observables for studying the hot, dense medium created in heavy ion collisions. They not only probe the collective flow of the bulk medium (at pT<3-4 GeV), but also probe the path-length dependent energy loss (at higher pT), both are associated with the asymmetries in the initial geometry. However, auto-correlations not related to initial geometry,...
Mr
Prithwish Tribedy
(for the STAR collaboration)
14/08/2012, 16:45
Correlations and fluctuations
Oral Presentation
Dynamical fluctuations in globally conserved quantities such as baryon
number, strangeness, charge, and isospin are suggested to carry information about the de-confinement and chiral phase transitions. An
observation of enhanced dynamical fluctuations or non-monotonic behavior of transverse momentum correlations as a function of colliding energy might indicate the system has probed the...
Matthew Nguyen
(Ecole Polytechnique (FR))
14/08/2012, 16:45
This presentation describes jet measurements in PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV performed with the CMS detector at the LHC.
With data from the 2011 Run, dijet measurements have been extended to large transverse momentum, up to 350 GeV/c. The dijet momentum balance and angular correlations are studied in detail as a function of collision centrality and...
Aaron Richard Angerami
(Columbia University (US))
14/08/2012, 17:05
Oral Presentation
The energy loss of high-pt partons through the phenomenon of jet quenching provides insight into the transport properties of the medium created in relativistic heavy ion collisions. Evidence for this energy loss was first experimentally established through observation of high-pt hadron suppression at RHIC. This observable is not ideal for detailed quenching measurements as the final state...
Heng-Tong Ding
(Brookhaven National Lab)
14/08/2012, 17:05
Oral Presentation
We study the momentum dependence of charmonia in a hot medium using lattice QCD calculations. We analyze correlation functions and extract spectral functions from quenched calculations on large lattices close to the continuum limit in the temperature region $1.5
Matthew Luzum
(IPhT Saclay)
14/08/2012, 17:05
Global and collective dynamics
Oral Presentation
We report an extraction of the ratio of shear viscosity to entropy density (eta/s) of the medium created in relativistic heavy-ion collisions at the LHC. With a significant improvement of one of the main sources of theoretical uncertainty, we are able for the first time to quote a precise average value with robust error bars, systematically accounting for all known sources of systematic error...
Michael Weber
(University of Houston (US))
14/08/2012, 17:05
Correlations and fluctuations
Oral Presentation
The creation of a strongly interacting deconfined Quark Gluon Plasma (QGP) phase in relativistic heavy-ion collisions can be studied by the fluctuations of conserved quantities like net-charge, and correlations between positive and negative pairs by using the method of Balance functions. Net-charge fluctuations are sensitive to the number of charges present in the system, thus the fluctuations...
Marguerite Belt Tonjes
(University of Maryland (US))
14/08/2012, 17:25
Measurements of charged hadron and inclusive jet transverse momentum (pT) spectra in pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV with the CMS detector will be reported. These measurements make use of the high-statistics jet-triggered data recorded in 2011, including the total available PbPb luminosity of 150/ub. Charged particles are reconstructed using an...
Ionut Cristian Arsene
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
14/08/2012, 17:25
Oral Presentation
The hot and dense nuclear matter created in nuclear collisions at relativistic energies consists of a plasma of deconfined quarks and gluons. Due to their large mass, the charm quarks are mainly formed in the first instants of the nuclear collision and will consequently experience the full history of the system. It was predicted that the strongly bound J/Ã state will be suppressed in the hot...
Maxime Rene Joseph Guilbaud
(Universite Claude Bernard-Lyon I (FR))
14/08/2012, 17:25
Oral Presentation
In this talk we present a measurement of the pseudorapidity distribution in the range −5 < eta < 5.25, for different centralities in Pb-Pb collisions at sqrt(s_NN) =2.76 TeV. This also allows us to estimate the total number of produced charged particles. The measurement is performed exploiting LHC satellite bunches, that is bunches captured in non-nominal RF buckets. These give rise to...
Ms
Lizhu Chen
(Central China Normal University)
14/08/2012, 17:25
Correlations and fluctuations
Oral Presentation
In high-energy nuclear collisions, we study the properties of the excited nuclear matter with QCD degrees of freedom and search for the signals of the QCD phase transition. The ratios of the cumulants of conserved number distributions are sensitive to the correlation length of the system created in heavy-ion collisions, hence they are considered as good observables to study phase transitions....
Kirill Tuchin
(Iowa State University)
14/08/2012, 17:45
Oral Presentation
We discuss the gluon saturation/color glass condensate effects on J/Psi production in high energy pA and AA collisions. We report the results of numerical calculations of the corresponding nuclear modification factors. We found a good agreement between our calculations and the experimental data on J/Psi production in pA collisions. We also observe that cold nuclear modification effects alone...
Yasuto Hori
(University of Tokyo (JP))
14/08/2012, 17:45
Oral Presentation
The charge dependence of the azimuthal correlations between produced hadrons is
an important probe of the QGP matter created in relativistic heavy-ion collisions. In
this talk, we will present the mixed harmonic charge dependent azimuthal correlations
measured at mid-rapidity in Pb-Pb collisions at \sqrt{s_{NN}} = 2.76 TeV by the ALICE Collaboration at the LHC. We observe a clear charge...
Dr
Magdalena Malek
(University of Illinois at Chicago (US))
14/08/2012, 17:45
Global and collective dynamics
Oral Presentation
The transverse energy flow in PbPb collisions at 2.76 TeV nucleon-nucleon center-of-mass energy has been measured over a broad range of centrality for pseudorapidities between -5.2 and 5.2 using the CMS detector at the LHC. This analysis is based on 0.306/ub of data from 2010, with recently extended number (and range) of pseudorapidity and centrality bins. The transverse energy per unit of...
Barbara Betz
(Frankfurt University)
14/08/2012, 17:45
Recent LHC data on the nuclear modification factor of jet fragments suggest that the jet-medium coupling at the Large Hadron Collider (LHC) may be reduced relative to the coupling at the Relativistic Hadron Collider (RHIC). We estimate the magnitude of that reduction
from a combined fit to the data on the nuclear modification factor and on the elliptic flow at both RHIC and LHC energies over...
Piotr Bozek
14/08/2012, 18:05
Oral Presentation
The puzzle of the fall-off of the same-side ridge in relative pseudorapidity, found in unbiased two-particle correlations, is solved. We show that the event-by-event hydrodynamics followed by statistical hadronization with proper charge conservation provides the crucial non-flow component and leads to agreement with the data at soft transverse momenta (p_T < 2 GeV). The fall-off of the...
Sangyong Jeon
(McGill University)
14/08/2012, 18:05
Global and collective dynamics
Oral Presentation
Hydrodynamic models enjoy much success in describing and predicting
the bulk dynamics of relativistic heavy ion collisions.
Recent studies have clearly shown that including initial and final fluctuations is essential for detailed study of the evolving QGP.
So far, however, not many studies appeared which incorporate both fluctuations at the same time.
Here we present our first results in...
Dr
Rishi Sharma
(TRIUMF)
14/08/2012, 18:05
Heavy flavor and quarkonium production
Oral Presentation
We calculate the yields of quarkonia in heavy ion collisions at RHIC and the LHC as a function of the transverse momentum. We focus on the consistent implementation of dynamically calculated nuclear matter effects, such as coherent power corrections, cold nuclear matter energy loss, and the Cronin effect in the initial state, and collisional dissociation of quarkonia in the final state as...
Rosi Jan Reed
(Yale University (US))
14/08/2012, 18:05
Oral Presentation
Measurements of high-pt particle production in heavy-ion collisions at RHIC have shown that medium-induced energy loss affects the partons produced in the early stage of a heavy-ion collision. The increased initial production cross section for partons at LHC energies makes fully reconstruted jets available in a wide kinematic range, which allows for a differential investigation of parton...
Prof.
Wolfgang Bauer
(Distinguished University Professor, Michigan State University)
14/08/2012, 19:00
Oral Presentation
Thomas Schaefer
(N)
15/08/2012, 08:30
Global and collective dynamics
Oral Presentation
We study the effects of bulk viscosity on $p_T$ spectra and
elliptic flow in heavy ion collisions. For this purpose we compute
the dissipative correction $\delta f$ to the single particle
distribution functions in leading-log QCD, and in kinetic
models of a hadronic resonance gas. We find that for a near
conformal fluid the bulk viscosity is suppressed by two powers
of the conformal...
Clemens Wohrmann
(KIT - Karlsruhe Institute of Technology (DE))
15/08/2012, 08:30
Pre-equilibrium and initial state dynamics
Oral Presentation
The energy flow at very high pseudorapidity in PbPb collisions is sensitive to the very low-x components of the nuclear wave-function. The CASTOR calorimeter extends the pseudorapidity coverage of CMS to -6.6, which is only 1.4 units away from the beam rapidity. A comparison of the centrality dependence of forward energy flow to that at lower pseudorapidities can shed light on the gluon...
Gojko Vujanovic
(McGill University)
15/08/2012, 08:30
The penetrating nature of dileptons makes them suitable probes to explore the properties of the strongly-interacting medium created in relativistic nuclear collisions. This study investigates thermal dilepton production using MUSIC (a Monotone Upstream-centered Scheme for Ion Collisions): a 3+1D hydrodynamic simulation with or without shear viscosity. We utilize dilepton emission rates that...
Thorsten Renk
(University of Jyväskylä)
15/08/2012, 08:30
Hard probes are a cornerstone in the ongoing program to determine the properties of hot and dense QCD matter as created in ultrarelativistic heavy ion collisions. The first two runs at the LHC have resulted in a wealth of measurements of both reconstructed jets and single inclusive high P_T hadrons, opening new kinematic windows and offering high statistics. Yet on first glance, several...
Dr
Ermias Atomssa
(Stony Brook University)
15/08/2012, 08:50
Measurements of lepton pair spectra are a crucial tool to map out the evolution of the hot dense matter created in ultra-relativistic heavy ion collisions. At low pair mass, direct photons and low mass vector mesons are the main center of interest. Interpretation of lepton pair production rates in excess of expectations from hadronic decays observed by PHENIX and how the data constrains...
Michael Strickland
(Gettysburg College)
,
Wojciech Florkowski
(Institute of nuclear Physics, Krakow)
15/08/2012, 08:50
Oral Presentation
Recently formulated model of highly-anisotropic and strongly dissipative hydrodynamics is used in 3+1 dimensions to study behavior of matter produced in ultra-relativistic heavy-ion collisions. We search for possible effects of the initial high anisotropy of pressure on the final soft-hadronic observables. We find that by appropriate adjustment of the initial energy density and/or the initial...
Bjoern Schenke
15/08/2012, 08:50
Global and collective dynamics
Oral Presentation
We present recent developments in describing anisotropic flow in heavy-ion collisions at the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory and the Large Hadron Collider (LHC) at CERN with a relativistic 3+1 dimensional viscous event-by-event hydrodynamic simulation.
We present results for elliptic, triangular and higher harmonic flow coefficients, including...
Leticia Cunqueiro
(Unknown-Unknown-Unknown)
15/08/2012, 08:50
Oral Presentation
To capture the full dynamics of the mechanisms of energy loss of hard partons in their passage through the dense medium created in Heavy Ion Collisions, jet reconstruction is required. In this
analysis we explore the radiation pattern of jets in Pb–Pb collisions at sqrt(s_NN) = 2.76 TeV and compare it to that of baseline pp jets at the same collision energy. Di-jets are selected by requiring...
Jamal Jalilian-Marian
(Baruch College)
15/08/2012, 09:10
Oral Presentation
Di-hadron azimuthal angular correlations in the forward rapidity region of deuteron-nucleus collisions at RHIC show a disappearance of the away side peak with centrality and transverse momentum. This can be understood, in the Color Glass Condensate (CGC) formalism, to be due to multi-gluon exchanges between the projectile and target. We show that CGC formalism predicts a similar disappearance...
Dr
Huang Bingchu
(Brookhaven National Lab)
15/08/2012, 09:10
Di-leptons serve as clean and bulk penetrating probes to study
the properties of the strongly interacting hot and dense medium
created in heavy ion collisions. They are produced in all stages
of the heavy-ion collisions and are not affected by strong
interactions, hence can probe the entire evolution of the
collision. Di-lepton production in the low mass range
($M_{ll}<1.1$ GeV/$c^{2}$)...
Dr
maki kurosawa
(RBRC)
15/08/2012, 09:10
Oral Presentation
Collective flow is one of the key measurements to study the hot and
dense matter created in heavy ion collisions, because it relates closely to early evolution of the matter. In particular, higher harmonic flow measurements plays an important role in constraining theoretical model calculations describing properties of the matter.
The silicon vertex tracker (VTX) was installed into the...
Pelin Kurt
(Vanderbilt University (US))
15/08/2012, 09:10
Jet shape measurements are important for many applications. When measured in pp collisions they can be used to constrain generator and showering settings. When measured in PbPb collisions they can be used to probe for distortions from energy loss in the hot and dense medium. Fully unfolded jet shape measurements will be presented and compared with generator expectations in 7 TeV pp collisions,...
Baldo Sahlmueller
15/08/2012, 09:30
Oral Presentation
While the study of the quark-gluon plasma has been the primary focus of the RHIC experiments, much work has also been done to understand so-called cold nuclear matter (CNM) effects through $d$+Au collisions where no hot plasma is produced. Effects such as nuclear shadowing, Cronin enhancement, and initial-state parton energy loss, among others, are not only interesting in their own right, but...
Martin Rybar
(Charles University (CZ))
15/08/2012, 09:30
Oral Presentation
The recent measurements of jet suppression at LHC indicate a presence of "jet quenching" -- strong energy loss of energetic jets in hot and dense QCD medium which has been already observed at RHIC experiments. We present a measurement of jet properties which sheds more light on the mechanism of jet energy loss. We will discuss the results of measurement of longitudinal, and transverse...
Prof.
Rainer Fries
(Texas A&M University)
15/08/2012, 09:30
Oral Presentation
We investigate the correlations of photons produced by back scattering of fast partons in quark gluon plasma
with their away‐side jets. Back scattering with photon emission, or jet‐photon conversion,
was originally proposed as a novel source of photons in Phys. Rev. Lett. 90, 132301 (2003).
The unique appeal of this photon source lies in the fact that its photons carry information about b...
Li Yi
(Purdue University)
15/08/2012, 09:30
Oral Presentation
Azimuthal anisotropic flows vn, arising from the anisotropic collision geometry, reflect the hydrodynamic properties of the quark gluon plasma created in relativistic heavy-ion collisions. A long standing issue in vn measurements is the contamination of nonflow, caused by intrinsic particle correlations unrelated to the collision geometry. Nonflow limits, in part, the precise extraction of the...
Frank Ma
(Massachusetts Inst. of Technology (US))
15/08/2012, 09:50
The jet fragmentation function of inclusive jets with pT > 100 GeV/c in PbPb collisions is measured for reconstructed charged particles with pT > 1 GeV/c within the jet cone. A data sample of PbPb collisions collected in 2011 at a center of mass energy of √sNN =2.76 TeV corresponding to an integrated luminosity of Lint = 129 μb−1 is used. The results for PbPb collisions as a function of...
Prof.
Ben-Wei Zhang
(Central China Normal University)
15/08/2012, 09:50
Parton energy loss in the hot QCD medium will manifest itself not only in leading hadron spectra but also in reconstructed jet productions in high-energy nucleus-nucleus collisions. With its more differential power full jets in heavy-ion collisions can then provide excellent tools to study the properties of the QGP and impose constraints on different parton energy loss models.
With this...
Martin Rudolf Wilde
(Westfaelische Wilhelms-Universitaet Muenster (DE))
15/08/2012, 09:50
Oral Presentation
Direct photons are an important probe in diagnosing the highly excited state of nuclear matter created in heavy-ion collisions: They allow access to various stages of the collision including the initial state.
The ALICE detector is equipped with two high resolution electromagnetic calorimeters and a central tracking system that make it well suited to study direct photon production at low...
Prof.
Chiho Nonaka
(Kobayashi-Maskawa Institute for the Origin of Particles and the Universe (KMI) and Department of Physics, Nagoya University)
15/08/2012, 09:50
Global and collective dynamics
Oral Presentation
Currently a possible origin of "Mach-Cone-like structure" is regarded as triangular
flow and higher harmonics which are produced through event-by-event fluctuated initial states, which is a push to implement effects of event-by-event fluctuations
in the initial conditions of relativistic hydrodynamic models.
When the hydrodynamic simulation is performed with initial conditions with the...
Paul Chesler
(MIT)
15/08/2012, 10:10
Oral Presentation
A remarkable result from heavy ion collisions at the Relativistic Heavy Ion Collider and Large Hadron Collider is that, shortly after the collision event, the quark-gluon plasma produced behaves as a nearly ideal liquid. Understanding the dynamics responsible for such rapid "hydroization" is a challenge using traditional perturbative field theory. In recent years holography has emerged as...
Fabio Dominguez
(IPhT Saclay)
15/08/2012, 10:10
The new studies of heavy ion collisions performed at the LHC have shown the necessity to improve our understanding of parton propagation and gluon emission in the presence of a hot QCD medium. In particular, the ability to measure jets in heavy ion collisions implies that, in order to fully understand jet quenching phenomena, we must go beyond leading parton energy loss and attempt to describe...
Mr
NASIM MD
(Variable Energy Cyclotron Centre)
15/08/2012, 10:10
Global and collective dynamics
Oral Presentation
One of the main goals of the STAR experiment at Relativistic Heavy
Ion Collider (RHIC) is to study the properties of the QCD
matter at extremely high energy and parton densities,
created in the heavy-ion collisions. Understanding the
partonic collectivity through the measurement of elliptic
flow ($v_{2}$) of multi-strange hadrons ($\phi$, $\Xi$ and $\Omega$)
is believed to be a sensitive...
Dr
shengli huang
(PHENIX Collaboration)
15/08/2012, 11:00
Oral Presentation
The number of quark ($n_q$) scaling, which is manifested
as $v^{hadron}_{2}(p_T) \approx n_q*v_2(p_T/n_q)$, is an
approximate scaling that comes from the addition of the valence
quark momenta at hadronization. The observation of $n_q$ scaling
has been claimed that a partonic matter with quark-like degrees
of freedom and significant collectivity has been generated in
heavy ion...
Jason Glyndwr Ulery
(Johann-Wolfgang-Goethe Univ. (DE))
15/08/2012, 11:00
Oral Presentation
Previous experimental measurements from nuclear collisions have indicated modifications of jets by interaction with the medium created in the collision. Observables from particle correlations in the ALICE detector continue to provide access to key properties of the hot deconfined nuclear matter. New results from two- and three-particle number and transverse momentum correlations are presented....
Iwona Grabowska-Bold
(AGH Univesity of Science and Technology (PL))
15/08/2012, 11:00
Oral Presentation
Direct photons are a powerful tool to study heavy ion collisions. Their production rates provide access to the initial state PDFs, which are expected to be modified by nuclear effects. They also provide a means to calibrate the expected energy of jets that are produced in the medium, and thus are a tool to probe the physics of jet quenching more precisely both through jet rates and...
Tuomas Lappi
(U)
15/08/2012, 11:00
Pre-equilibrium and initial state dynamics
Oral Presentation
Multiparticle correlations, such as the "ridge" effect in pp and AA collisions and forward dihadron correlations in pA collisions, are an important probe of the strong color fields that dominate the initial stages of a heavy ion collision. We argue that the Color Glass Condensate framework provides the most natural way to understand them.
We describe recent progress in understanding...
Long-Gang Pang
(l)
15/08/2012, 11:20
Global and collective dynamics
Oral Presentation
Hadron spectra and elliptic flow in high-energy heavy-ion collisions are studied within a (3+1)D ideal hydrodynamic model with fluctuating initial conditions given by the AMPT Monte Carlo model and compared to experimental data. Fluctuation in the initial energy density comes from not only the coherent soft interaction of overlapping nucleons but also the number of mini-jets within each binary...
George Stephans
(Massachusetts Inst. of Technology (US))
15/08/2012, 11:20
Final data on isolated photon production will be presented, measured in both pp and PbPb collisions at a nucleon-nucleon center-of-mass energy of 2.76 TeV with the CMS detector at the LHC. The isolated photon transverse energy (ET) spectra, covering the pseudorapidity range |eta| < 1.44 and transverse energy ET > 20 GeV, are found to be in good agreement with next-to-leading-order perturbative...
Jiangyong Jia
(Brookhaven National Laboratory (BNL)-Unknown-Unknown)
15/08/2012, 11:20
Oral Presentation
A study of the dipole flow (v_1) associated with initial geometry fluctuations is presented using the 2010 Pb-Pb data. This analysis involves a systematic decomposition of the first order Fourier coefficient of the two-particle correlation into a dipole flow component and a global momentum conservation component. The dipolar flow is extracted as function of pT (0.5-10 GeV), centrality (0-50%)...
Filip Krizek
(Helsinki Institute of Physics (FI))
15/08/2012, 11:20
Oral Presentation
A high-$p_{T}$ jet suppression first observed at RHIC has been reported also at the LHC.
The ALICE collaboration has recently reported an observation of an enhanced intra-jet yield of charged particles associated with the high-\pt{} trigger particle ($I_{\rm AA}$) in central \pbpb\ collisions at \snn=2.76 \tev\ which may be also interpreted as a hint of the modification of the fragmentation...
Karel Safarik
(CERN)
15/08/2012, 11:40
Oral Presentation
A baryon anomaly – an increase baryon-to-meson production ratio at intermediate transverse momenta in heavy-ion collisions when compared to proton–proton collisions – is observed at RHIC and the LHC. This effect is usually explained by recombination of constituent quarks during QGP hadronisation, or as a consequence of a strong radial flow developed during the heavy-ion collision. In this...
Mr
J. Scott Moreland
(Duke University)
15/08/2012, 11:40
Pre-equilibrium and initial state dynamics
Oral Presentation
The precise value of the QGP kinematic shear viscosity eta/s is a question of intense topical interest. Viscous hydrodynamic simulations are a tool for extracting this information from experiment. The key observables are the anisotropic flow coefficients v_n which (i) can be measured very precisely and (ii) are very sensitive to eta/s which controls the "conversion efficiency" v_n/ecc_n for...
Alice Ohlson
(Yale University)
15/08/2012, 11:40
The relationship between jet properties and the underlying geometry of the medium produced in heavy ion collisions can be explored through a measurement of the correlation between the axes of reconstructed jets and the reaction plane (defined as jet $v_2$). Such a measurement provides information on the pathlength dependence of medium-induced parton energy loss as well as biases in...
Jiri Dolejsi
(Charles University (CZ))
15/08/2012, 11:40
Oral Presentation
Collisions of lead nuclei at the LHC allow study of the deconfined phase of QCD matter at unparalleled temperatures and energy densities. The use of leptonic observables is particularly appealing as a consequence of their electroweak nature, allowing them to traverse the strongly-coupled medium essentially unaffected. W and Z bosons, observed through their semi-leptonic decay channels, may...
Michal Broz
(Comenius University (SK))
15/08/2012, 12:00
Global and collective dynamics
Oral Presentation
The ALICE Experiment features low material budget and high resolution tracking, which allow for precise measurements of charged particle production.
The measurement of the antibaryon to baryon ratios ($\bar{B}$/B), in particular, probes the baryon transport and the degree of baryon stopping in high energy collisions, providing insight into the collision dynamics and the structure of baryons....
Dmitri Peresunko
(National Research Centre Kurchatov Institute (RU))
15/08/2012, 12:00
Oral Presentation
Identified hadron spectra are considered to be sensitive to transport properties of strongly interacting matter produced in high-energy nucleus-nucleus collisions.
We present measurements of $\pi^0$ and $\eta$ mesons at mid-rapidity in a wide transverse momentum range in pp and Pb-Pb collisions at LHC energies measured with the ALICE detector. The mesons are reconstructed via their...
Raju Venugopalan
(Brookhaven National Laboratory)
15/08/2012, 12:00
Pre-equilibrium and initial state dynamics
Oral Presentation
We outline significant recent progress in a program to include quantum corrections to the evolution of the classical color fields produced in high-energy ultra-relativistic heavy ion collisions. Previous work in this direction for a scalar \phi^4 theory [1] has now been extended to QCD. Leading contributions from unstable quantum modes can be resumed to all loop orders and expressed in terms...
Lamia Benhabib
(Ecole Polytechnique (FR))
15/08/2012, 12:00
The Compact Muon Solenoid (CMS) is fully equipped to measure leptonic decays of electroweak probes in the high multiplicity environment of nucleus-nucleus collisions. Electroweak boson production is an important benchmark process at hadron colliders. Precise measurements of W and Z production in heavy-ion collisions can help to constrain nuclear PDFs as well as serve as a standard candle of...
Xuan Li
(Shandong University)
15/08/2012, 12:20
Pre-equilibrium and initial state dynamics
Oral Presentation
The proton gluon distribution function increases rapidly with decreasing x at fixed $Q^{2}$, but cannot increase indefinitely as x goes to 0. Gluon saturation is expected at a low x value when gluon recombination balances gluon splitting. The nuclear (with atomic mass number A) gluon distribution is approximately $A^{1/3}$ larger than the nucleon gluon distribution function at the same x [1]....
Gian Michele Innocenti
(Universita e INFN (IT))
15/08/2012, 12:20
Oral Presentation
The measurement of heavy-flavour production provides insights on the properties of the high-density QCD medium created in heavy-ion collisions.
In particular, the comparison of charm production in pp and in Pb-Pb collisions allows to study the mechanism of in-medium energy loss of heavy quarks. Furthermore, since strange quarks are abundant in the medium, the relative yield of D+s mesons with...
Frank Geurts
(Rice University (US))
16/08/2012, 08:30
Oral Presentation
Itzhak Tserruya
(Weizmann Institute of Science (IL))
16/08/2012, 08:55
Oral Presentation
Peter Alan Steinberg
(Brookhaven National Laboratory (US))
16/08/2012, 09:20
Oral Presentation
Raphael Granier De Cassagnac
(Ecole Polytechnique (FR))
16/08/2012, 09:45
Oral Presentation
Camelia Mironov
(Ecole Polytechnique (FR))
16/08/2012, 11:05
Oral Presentation
Enrico Scomparin
(Universita e INFN (IT))
16/08/2012, 11:25
Oral Presentation
Tetsuo Hatsuda
(Unknown)
16/08/2012, 11:45
Oral Presentation
16/08/2012, 12:05
Gang Wang
(UCLA)
16/08/2012, 12:20
Oral Presentation
Dr
Abhijit Majumder
(Wayne State University)
16/08/2012, 14:00
Oral Presentation
The in-medium modification of a hard jet is reformulated to consider the process of a hard parton propagating through a finite sized QCD medium, held at a fixed high temperature and vanishing chemical potential. The process is factorized into a hard part representing the propagation and scattering of the parton, and a soft part representing the non-perturbative color field experienced by the...
Leonardo Milano
(Universita e INFN (IT))
16/08/2012, 14:00
Hadron thermodynamics and chemistry
Oral Presentation
Identified particle spectra are a basic observable to understand the behaviour of the matter created in high-energy heavy-ion collisions. The transverse momentum distributions of identified hadrons contain informations about the transverse expansion of the system and constrain the freeze-out properties of the matter created. The ALICE experiment has very good particle identification...
Derek Teaney
(Stony Brook University)
16/08/2012, 14:00
Oral Presentation
We determine the photon production rate at next to leading order, i.e. through order $g^2 m_D/T$. At leading order, photon production is determined by three processes: hard two-to-two collisions, collinear bremsstrahlung, and quark-conversions, i.e. a process where the incoming quark transfers almost all of its momentum to the produced photon and the final state quark is soft. At NLO, wider...
Christopher Coleman-Smith
(Duke Physics)
16/08/2012, 14:00
Recent results from Pb+Pb collisions at the LHC have shown evidence of dramatic medium modification of di-jets. Although asymmetric di-jets are also seen in p+p collisions, di-jets with a large energy asymmetry are found much more often in Pb+Pb collisions. E.g., events with a 200 GeV leading jet and a 80 GeV subleading jet were frequently observed. The increase in the average energy asymmetry...
Paul Romatschke
(FIAS Frankfurt)
16/08/2012, 14:20
Oral Presentation
Hydrodynamics predicts long-lived sound and shear waves.
Thermal fluctuations in these waves can lead to the diffusion of
momentum density, contributing to the shear viscosity and other
transport coefficients. Within viscous hydrodynamics in 3+1
dimensions, this leads to a positive contribution to the shear
viscosity, which is finite but inversely proportional to the
microscopic shear...
Antonio Ortiz Velasquez
(Lund University (SE))
16/08/2012, 14:20
Oral Presentation
The main tracking detector in the central barrel ($|\eta|<1$) of the ALICE experiment is the Time Projection Chamber. In addition to charged particle tracking it provides particle identification (PID) through the measurement of the specific energy loss, $dE/dx$. At low momentum ($p < 1$ GeV/c), pions, kaons, and protons can be cleanly separated. Thanks to the relativistic rise of the $dE/dx$,...
Peter Braun-Munzinger
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
16/08/2012, 14:20
Hadron thermodynamics and chemistry
Oral Presentation
We investigate, using the newest LHC data, the energy
dependence of hadron production within the framework of the
statistical hadronization model. The data are confronted with
predictions based on extrapolation from lower (RHIC) energies. While
the yields of hadrons made from light (u,d,s) quarks generally exhibit
little change apart from the overall increase in
multiplicity, a...
Mindaugas Lekaveckas
(MIT)
16/08/2012, 14:20
Oral Presentation
We calculate P(k_perp), the probability distribution for an energetic parton propagating for a distance L through a medium to pick up transverse momentum k_perp, for a medium consisting of weakly coupled quark-gluon plasma. We use full or HTL self-energies in appropriate regimes, resumming each in order to find the leading large-L behavior. We estimate the jet quenching parameter and compare...
Petr Balek
(Charles University (CZ))
16/08/2012, 14:40
Oral Presentation
The measurement of charged particle spectra in heavy ion collisions is a direct way to study properties of hot and dense matter created in these interactions. The centrality dependence of the spectral shape is an important tool to understand the energy loss mechanism. The ATLAS detector at the LHC accumulated 150µb-1 of lead-lead data at 2.76 TeV per nucleon-nucleon pair. Due to the excellent...
Peter Arnold
(University of Virginia)
16/08/2012, 14:40
Oral Presentation
Previous top-down studies of jet stopping in strongly-coupled QCD-like plasmas with gravity duals have been in the infinite 't Hooft coupling limit $\lambda \to \infty$. They have found that, though a wide range of jet stopping distances are possible depending on initial conditions, the maximum jet stopping distance $\ell_{\rm max}$ scales with energy as $E^{1/3}$ at large energy. But it has...
Dr
Christian Schmidt
(Universitaet Bielefeld)
16/08/2012, 14:40
Oral Presentation
We calculate electric and baryonic charge fluctuations on the lattice. Results have been obtained with the highly improved staggered quark action (HISQ) and almost physical quark masses on lattices with temporal extent of N_tau=6,8,12. Higher cumulants of the net-charge distributions are increasingly dominated by a universal scaling behavior, which is arising due to a critical point of QCD in...
Subhash Singha
(Department of Atomic Energy (IN))
16/08/2012, 14:40
Hadron thermodynamics and chemistry
Oral Presentation
The ALICE experiment at the LHC has measured the production of strange hadrons and resonances in Pb-Pb and pp collisions at unprecedentedly high beam energies. The study of strange hadrons and resonances helps us to understand the medium properties and its evolution at dierent stages.
We will present the pT spectra and yields at mid-rapidity for strange hadrons (,
labda, xi, omega, their...
Dr
Xiaoping Zhang
(Tsinghua University)
16/08/2012, 15:00
Global and collective dynamics
Oral Presentation
Strange hadron production is sensitive to parton dynamics in nucleus-nucleus collisions. In particular, the strange quark production rate and its subsequent evolution in the dense partonic medium depend on the beam energy and the net baryon density. We will present STAR measurements of $K^{0}_{s}$, $K^{\pm}$, $\phi$, $\Lambda$, $\Xi$, and $\Omega$ at mid-rapidity from Au+Au collisions at...
Dr
Claudia Ratti
(Torino University)
16/08/2012, 15:00
QCD at finite temperature and density
Oral Presentation
We present our estimate for the charm quark's contribution to
the equation of state and to the fluctuations of conserved charges.
Our results are based on simulations with dynamical charm at
physical quark masses. We also address the question, to what extent
staggered simulations are reliable. We give comparisons with the Wilson
formulation as well as with results using dynamical overlap fermions.
Benjamin Doenigus
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
16/08/2012, 15:20
Hadron thermodynamics and chemistry
Oral Presentation
The excellent particle identification capabilities of the ALICE experiment allow the studies of (anti) matter and hyper-matter production. (Anti) deuterons, tritons, 3He and 4He as well as the corresponding antinuclei can be cleanly identified based on their specific energy loss in the Time Projection Chamber and velocity information in the Time-Of-Flight detector. The (anti) hyper-triton...
Dr
Yacine Mehtar-Tani
(IPhT-Saclay)
16/08/2012, 15:20
Oral Presentation
The recent jet measurements at RHIC and the LHC have challenged the heavy-ion community to a better understanding of jet fragmentation in the presence of the Quark-Gluon-Plasma (QGP).
Jet fragmentation in vacuum is well described by perturbative QCD and is characterized by color coherence effects that lead to the angular ordering of successive branchings along the jet. To investigate the...
Swagato Mukherjee
(Brookhaven National Laboratory)
16/08/2012, 15:20
Oral Presentation
Traditionally the freeze-out conditions in the heavy-ion collision experiments are obtained by comparing the experimentally measured hadron yields with that from the statistical hadron resonance gas model. In this talk we will present how the freeze-out chemical potentials and the freeze-out temperature can be obtained in a model independent way from ab-initio lattice QCD calculations by...
Dr
Prashant Shukla
(Bhabha Atomic Research Centre (IN))
16/08/2012, 15:20
Oral Presentation
The hadrons containing strange quark(s) are among the most interesting probes of the hot and dense matter produced in heavy ion collisions at Relativistic Heavy Ion Collider (RHIC). While p+p collisions are used as a baseline for comparison with heavier collision systems and provide a cross check for pQCD calculations, d+Au collisions are used to study cold nuclear matter effects for mesons...
Alessandro Buzzatti
(Columbia University)
16/08/2012, 15:40
Oral Presentation
The CUJET1.0 Monte Carlo Jet Energy loss model is applied to predict the jet flavor, centrality and density dependence of the nuclear modification factor $R_{AA}$ and the elliptic flow $v_2$ at RHIC and LHC. Running coupling effects due to combined $x$, $k_\perp$ and $q_\perp$ evolution are included for the first time in the dynamical DGLV opacity expansion framework and are shown to provide a...
Ms
Yuhui Zhu
(Shanghai Institute of Applied Physics)
16/08/2012, 15:40
Global and collective dynamics
Oral Presentation
The hyperon-nucleon(Y-N) interaction is of great physical interest because it introduces a new quantum number strangeness in nuclear matter. It is predicted to be the decisive interaction in some high-density matter systems, such as neutron stars [1]. RHIC, the Relativistic Heavy Ion Collider, provides an ideal laboratory to study Y-N interaction because hyperons and nucleons are abundantly...
Dr
Robert Pisarski
(Brookhaven National Lab.)
16/08/2012, 15:40
QCD at finite temperature and density
Oral Presentation
An effective theory for the region near the critical temperature, the "semi"-QGP, has been developed. In QCD, this is dominated by the partial ionization of color, up to temperatures about 300 MeV. Using the effective model, the temperature dependence for the ratio of the shear viscosity, to the entropy, is computed. This predicts a sharp increase in this ratio between ~ 160 MeV and ~ 300 MeV.
Alexei Bazavov
(B)
16/08/2012, 15:40
Oral Presentation
The physics of the Quark-Gluon Plasma (QGP), currently explored experimentally in heavy-ion collisions, is non-perturbative for temperatures below approximately 1 GeV. One of the fundamental properties of the QGP, the Equation of State, is a subject of extensive studies in lattice QCD. The lattice QCD Equation of State is now an essential requirement for the correct hydrodynamic modeling of...
Prof.
Vincenzo Greco
(University of Catania)
16/08/2012, 16:00
We study the evolution of the quark-gluon composition of the plasma created in ultra-Relativistic-Heavy Ion Collisions (uRHIC's) employing a partonic transport theory that includes both elastic and inelastic collisions plus a mean fields dymanics associated to the widely used quasi-particle model. The latter, able to describe lattice QCD thermodynamics, implies a "chemical" equilibrium ratio...
Riccardo Russo
(Universita e INFN (IT))
16/08/2012, 16:00
Open heavy flavour hadrons produced in high-energy ion collisions are an interesting tool to investigate the properties of the QCD medium, as they come from the hadronization of heavy quarks which are created in the early stage of the interaction and which experience the whole collision history.
Energy loss of heavy quarks in the medium can be investigated by comparing the heavy flavour...
J. Matthew Durham
(Los Alamos National Laboratory)
16/08/2012, 16:00
The flexibility of the beam species available at the Relativistic
Heavy Ion Collider has enabled the PHENIX Collaboration to examine
open heavy flavor production across a wide range of temperature,
energy density, and system size. Charm and bottom production in
$p+p$ collisions, which is dominated by gluon fusion, is largely
consistent with FONLL pQCD calculations. New analysis...
Prof.
Yuanfang Wu
(Institute of Particle Physics, CCNU, Wuhan China)
16/08/2012, 16:00
The radial flow parameters are important quantities in relativistic heavy ion collisions [1]. They constrain the equation of state [2] and in particular, the anisotropic parameter relates to shear viscosity [3]. They are usually extracted from the spectrum of transverse momentum by the parameterizations of Blast-wave model [4].
In the present work, we suggest a direct measure of radial...
Taku Gunji
(University of Tokyo (JP))
16/08/2012, 16:00
The Time Projection Chamber (TPC) is the central tracking device of the ALICE experiment, providing momentum measurement and particle identification via the specific energy loss dE/dx. The readout rate of the TPC is presently limited by the necessity to prevent ions from the amplification region of the MWPC-based readout chambers to drift back into the drift volume, which is achieved through...
499.
A novel high momentum particle identification detector for the next generation ALICE experiment
Austin Vincent Harton
(Chicago State University (US))
16/08/2012, 16:00
A high momentum particle identification detector is under discussion by the ALICE experiment at CERN as part of its plan for high luminosity data taking in the next decade. The VHMPID detector is improving on well established ring imaging Cerenkov technology by using a pressurized gas volume in a focussing geometry to minimize the radial depth of the device. In this configuration the VHMPID...
Kurt Jung
(Purdue University (US))
16/08/2012, 16:00
Dileptons are unique probes of the strongly-coupled Quark Gluon Plasma (QGP) created in relativistic heavy-ion collisions. Compared to hadrons, leptons have little interaction with the QGP medium and can thus travel through the entire system with most of the original information intact. This feature allows us to study the properties of the medium during its space-time evolution. The low mass...
Michael McCumber
(University of Colorado)
16/08/2012, 16:00
The PHENIX experiment at the Relativistic Heavy Ion Collider recently took data in p+p and Au+Au collisions with a new silicon vertex detector (VTX). This upgrade detector is capable of measuring the off-vertex decay of heavy flavor decay electrons via distance of closest approach (DCA). The resulting measured DCA distributions will be a convolution of the parent meson momenta, decay...
Nikola for the ALICE-FoCal collaboration Poljak
(NIKHEF/Univeristy of Utrecht)
16/08/2012, 16:00
A forward electromagnetic calorimeter (FoCal), to be placed in the pseudorapidity range of $2.5<\eta<4.5$, is being discussed as one of the upgrade plans for the LHC-ALICE experiment. One of the motivations for building such a detector is the study of direct photons, as well as correlations including photons, pions and jets in pp,pA and AA collisions at the highest LHC energies. Such...
Xiangrong Zhu
(Central China Normal University CCNU (CN))
16/08/2012, 16:00
Neutral pion production measured with the ALICE detector in Pb-Pb collisions at the LHC is an important tool to study the properties of the hot and dense medium created in heavy-ion collisions.
The neutral pion yield, obtained with the ALICE electromagnetic calorimeter in pp collisions at sqrt(s) = 2.76 and 7 TeV, as well as in Pb-Pb collisions at sqrt(s_NN) = 2.76, is analyzed in terms of...
Dr
Frederique Grassi
(Universidade de Sao Paulo, Brazil)
16/08/2012, 16:00
We calculate flow observables with the NeXSPheRIO ideal hydrodynamic model and make the first comparison to the complete set of mid- rapidity flow measurements made by the PHENIX collaboration in top energy Au+Au collisions. A simultaneous calculation of v2, v3, v4, and the first event-by-event calculation of quadrangular flow defined with respect to the v2 event plane (v4{psi2}) gives...
You Zhou
(Nikhef and Utrecht University (NL))
16/08/2012, 16:00
The $\phi$-meson flow is seen as an important observable to study hydrodynamic behavior and partonic collectivity of heavy-ion collisions. We present detailed measurements of $\phi$-meson flow in $\sqrt{s_{NN}}$=2.76 TeV Pb--Pb collisions with the ALICE detector. The results are compared to the flow of other identified particles (kaons, pions, antiprotons, lambdas, cascades ) to investigate...
Mr
Yuji Hirono
(The University of Tokyo)
16/08/2012, 16:00
Quantum vortices in the color-flavor locked (CFL) phase of QCD have bosonic degrees of freedom localized on them, called the orientational zero modes. We show that the orientational zero modes are electromagnetically charged. As a result, a vortex in the CFL phase nontrivially interacts with photons. We show that a lattice of vortices acts as a polarizer of photons with wavelengths larger than...
Joshua Ilany
(Department of Physics and Astronomy, Stony Brook University, Stony Brook, New York 11794-3800, USA)
16/08/2012, 16:00
Anomalous soft photon production beyond that predicted by standard Bremsstrahlung calculations is a ubiquitous feature in high energy processes, from e+e- to heavy ion collisions. We calculate the electromagnetic current due to the QCD vacuum polarization induced by the qq jets in e+e- annihilation using the Schwinger model, and source Maxwell’s equations with it. The predicted soft photon...
Shikshit Gupta
(University of Jammu)
16/08/2012, 16:00
Information about the evolution of the system formed during the high energy p + p collisions can be obtained by investigating the charged particle ratios. The particle ratios serve as an important indicator of the collision dynamics [1]. These can be used to probe the process of hadronization in high energy collisions. In this poster, we will present measurements of mid-rapidity antiparticle...
Mr
Christopher Yaldo
(Wayne State University)
16/08/2012, 16:00
The main difficulty in precise and systematically controlled jet measurements in heavy-ion collisions is the correction for the soft underlying background fluctuation as well as for additional hard scatterings occurring in the nucleus-nucleus collision. To minimize non-trivial biases in jet-quenching measurements by imposing kinematical constraints on the jet fragmentation and to suppress...
Heikki Mäntysaari
(University of Jyväskylä, Department of Physics)
16/08/2012, 16:00
Single inclusive hadron production in the forward rapidiy region in
deuteron-gold collisions is well understood in the Color Glass Condensate (CGC) framework. As a complement to single inclusive spectra, detailed information is obtained with two-particle correlations. Recent measurements of the azimuthal angle correlations at RHIC have shown that there is a strong suppression of the away...
Deepa Thomas
(University of Utrecht (NL))
16/08/2012, 16:00
The measurement of heavy-flavour (charm and beauty) production in ultra-relativistic heavy ion collisions provides an important test of the parton energy loss mechanism and its predicted color charge and parton mass dependencies. The suppression of electron yields from semi-leptonic decays of D and B mesons in Pb-Pb collisions at the LHC has been observed to be large. Because of the dead-cone...
Mohammed Younus
(Variable Energy Cyclotron Centre)
16/08/2012, 16:00
We present the azimuthal correlation of charm, anti-charm pairs produced at LHC energies. We show our results for both proton on proton collision as well as lead on lead collision.
An empirical model has been included to show the effect of
energy loss on the correlation . Separately an effect of collective flow using blast wave model on the correlation is also shown.
Bogdan Theodor Rascanu
(Johann-Wolfgang-Goethe Univ.)
16/08/2012, 16:00
In ultra-relativistic heavy-ion collisions, charm and beauty quarks are a sensitive tool to probe the flavour and mass dependence of the parton interaction with the medium created in such interactions, the Quark-Gluon Plasma.
The level of thermalization of heavy quarks can be studied via the azimuthal anisotropy of their emission in the transverse plane, the elliptic flow v2, at low...
Alis Rodriguez Manso
(NIKHEF (NL))
16/08/2012, 16:00
The possible creation of a strongly interacting deconfined phase (Quark-Gluon plasma) in relativistic heavy ion collisions would be measurable in a delayed hadronization time. It was proposed to test this hypothesis via the measurement of correlations between positive and negatively charged pairs pairs as a function of rapidity, the so-called Balance functions, which was done at SPS and RHIC...
Dr
Kenji Morita
(Kyoto University)
16/08/2012, 16:00
We discuss the influence of the chiral phase transition on the properties
of the probability distribution of conserved charges based on effective chiral
models and on the Landau theory of phase transition [1].
Statistical fluctuations of the net baryon number have been regarded as a
diagnostic tool of the chiral phase transition in QCD and in heavy ion collisions.
Normally, they are...
Enrico Fragiacomo
(Universita e INFN (IT))
16/08/2012, 16:00
The study of resonances production in p-p collisions provides constraints on QCD-inspired particle production models.
In Pb-Pb collisions, resonances are good probes to estimate the collective properties of the fireball and may add constraints to the estimate of its lifetime.
$p_T$ spectra have been measured for the baryonic resonances $\Lambdastar$, $\Sigmastar$ and $\Xistar$ using data...
Hui Wang
(Michigan state university)
16/08/2012, 16:00
The study of correlations between opposite sign charge pairs can provide a powerful tool to probe the properties of the quark-gluon plasma (QGP). The balance function, which measures the correlations between opposite sign charge pairs, is sensitive to the mechanisms of charge formation and the subsequent relative diffusion of the balancing charges. The study of the balance function can provide...
Michal Petran
(Czech Technical University (CZ))
16/08/2012, 16:00
The short lifespan of the QCD phase at RHIC and LHC suggests fast filamenting disintegration of the supercooled QGP state of matter. The ensemble of all produced hadrons carry information about the physical properties of the disintegrating QGP. For example the energy content is obtained evaluating the energy carried by all hadrons. Considering that many of the particles have not been...
Andrej Ficnar
(Columbia University in the City of New York)
16/08/2012, 16:00
We present new solutions for holographic falling string models of light quark jet energy loss that suggest a linear path dependence of energy loss, dE/dx ~ x^1, without the nonlinear x^2 dependence assumed previously. This effect, combined with non-conformal deformations and higher curvature corrections of AdS geometry, is shown to be able to account for the small relative reduction of the...
Xiangli Cui
(U)
16/08/2012, 16:00
Di-leptons are ideal probes of the strongly interacting hot and dense
medium created at RHIC. They are not affected by the strong interaction once produced, therefore they can probe the whole evolution of the collision. The di-leptons spectra in the intermediate mass range ($1.1
387.
Charge Asymmetry Dependency of $\pi^+/\pi^-$ Azimuthal Anisotropy in Au + Au Collisions at STAR
Hongwei Ke
(Central China Normal University)
16/08/2012, 16:00
A recent theoretical study indicates that a chiral magnetic wave at finite baryon density could induce an electric quadrupole moment in the quark-gluon plasma produced in heavy ion collisions. The quadrupole deformation will lead to a difference in azimuthal anisotropy $v_2$, between positive and negative pions, and the magnitude of this difference is predicted to be proportional to net charge...
Guo-Liang Ma
(Shanghai INstitute of Applied Physics (SINAP), CAS)
16/08/2012, 16:00
With a multi-phase transport model including initial charge separation and string melting, the charge azimuthal correlations for Au+Au collisions at center of mass energies 200, 39, 11.5, 7.7 GeV and Pb+Pb collisions at 2.76 TeV are investigated. Initial charge separations of about 10 % for 200 GeV, 5 % for 39 GeV, 0 % for 11.5 GeV appear to be necessary. This is consistent with decreasing...
Charles Riley
(Yale University)
16/08/2012, 16:00
Three-particle correlations have been used to probe for local parity violation (LPV) in the quark-gluon plasma (QGP) formed during Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV at RHIC [1]. Further expanding on this analysis, we present our results on looking at these correlations through pairing kaons and pions produced during the collision events (while fixing the third particle to be...
Jocelyn Mlynarz
(Wayne State University (US))
16/08/2012, 16:00
Charge dependent azimuthal correlations relative to the reaction plane measured by the STAR collaboration at RHIC and ALICE at the LHC are consistent with expectations from the strong local parity violation in QGP manifesting itself via the Chiral Magnetic Effect. The background to these measurements comes from interplay of strong anisotropic flow and correlations not related to CME. In this...
Michal Petran
(Czech Technical University (CZ))
16/08/2012, 16:00
Almost all charm in heavy ion collisions is produced in the hard 'first interaction' processes before partons thermalize into a drop of QGP. Charm survives the QGP evolution and as hadrons emerge in soft hadronization processes, practically every charm or anticharm quark turns into a charmed hadron, small fraction of the charm yield enters multi-charmed hadrons and charmonium states. We...
Peter Levai
(Hungarian Academy of Sciences (HU))
16/08/2012, 16:00
The charm quark production will be reasonably large at LHC energies, both in p+p and Pb+Pb collisions. In heavy ion collisions even quark coalescence channels will strongly influence the charmed baryon and meson production. Furthermore, the formation of an intense coherent gluon field in Pb+Pb collisions results in additional heavy quark-antiquark pairs. Thus the primary charm quark momentum...
Dr
Alexandre Lebedev
(Iowa State University)
16/08/2012, 16:00
Measurement of different quarkonia states is a well known
tool for study of hot and dense matter produced in heavy ion
collisions.
The PHENIX experiment at RHIC have successfully measured
chi_c production in p+p and d+Au collisions at 200 GeV.
The chi_c decays were reconstructed through their decays to J/Psi+gamma.
Results from the 2006 p+p and 2008 d+Au
datasets at 200GeV will be...
Mr
Vasily Sazonov
(University of Graz)
16/08/2012, 16:00
The question of the existence of a confining matter with restored chiral
symmetry at low temperatures and large density has been studied within
the confining and chirally symmetric model, assuming a rigid quark Fermi surface. However, in the confining matter near the Fermi surface quarks group into color-singlet baryons. Due to the interaction between quarks the quark Fermi surface gets...
Christian Wesp
(Goethe Universität Frankfurt)
16/08/2012, 16:00
One of today's main goals in high energy physics is the exploration of the phase diagram of nuclear matter.
On the theoretical side, much effort has been put into the investigation of quantum chromodynamics (QCD), its phase diagramm and symmetries.
An important property of the QCD Lagrangian is its approximate chiral symmetry in the light-quark sector. At low temperatures and density this...
Edward Shuryak
(stony brook university)
16/08/2012, 16:00
For about a decade it is known that topological fluctuations -- instantons
-- are modified by the nonzero Polyakov line VEV and split into Nc dyons.
By now there is extensive lattice literature confirming this fact and
explaining certain observations by properties of such dyons, mostly at T=(1-2)Tc.
This talk report the first direct simulations of the statistical mechanics
of the...
Dr
brijesh srivastava
(Purdue University)
16/08/2012, 16:00
The shear to viscosity ratios ($\eta/s$) are obtained for the QGP in the context of the Color String Percolation Model (CSPM) using data produced in Au-Au collisions at $\sqrt{s_{NN}}$ = 200 A GeV at RHIC and Pb-Pb at $\sqrt{s_{NN}}$ = 2.76 TeV at LHC \cite{per}. The experimental transverse momentum spectrum is used to measure the percolation density parameter $\xi$ in Au-Au collisions...
Kwangbok Lee
(Losalamos National Laboratory)
16/08/2012, 16:00
$\Upsilon(1S+2S+3S)$ are measured in $d$ + Au and $p$ + $p$ collisions
at $\sqrt{s_{NN}} $= 200 GeV by the PHENIX experiment in the di-muon decay channel
at 1.2 < |y| < 2.2. Compared to the $J/\psi$, the $Upsilon$'s heavier mass makes it possible to
study the nuclear effects on the gluon distribution in different kinematic regions than those
probed by the $J/\psi$. The measured results...
Dr
Armen Sedrakian
(Frankfurt University)
16/08/2012, 16:00
I discuss the structure and composition of massive (two solar-mass) neutron stars containing deconfined quark matter in color superconducting states. Stable configurations featuring such matter are obtained if the equation of state of hadronic matter is stiff above the saturation density, the transition to quark matter takes place at a few times the nuclear saturation density, and the...
Prof.
Alexandru Jipa
(Faculty of Physics, University of Bucharest)
16/08/2012, 16:00
Heavy-ion collisions at relativistic energies ofer an unique opportunity to probe highly excited dense nuclear matter with properties very diferent from that of a hadron gas or ordinary nuclear matter in the laboratory. An interesting phenomenon at the kinetic freeze-out stage of the system evolution is the collective transverse expansion as it is entirely generated during the collision and...
Dr
Irakli Garishvili
(Lawrence Livermore National Laboratory)
16/08/2012, 16:00
Constraining properties of the strongly interacting state of matter produced in relativistic heavy ion collisions at RHIC and LHC, such as eta/s and T_{init} is one of the biggest priorities in the field of heavy ion physics. For this purpose, we have developed CHIMERA, a framework for performing global statistical evaluation of multiple QGP signatures by comparing key soft observables...
Dr
Thomas Hell
(Technische Universität München)
16/08/2012, 16:00
Recently, the mass of the pulsar PSR J1614-2230 has been measured at a one-percent accuracy to be roughly two solar masses. This, in addition to the statistical analysis of neutron-star radii by Steiner, Lattimer, and Brown lead to tight constraints for the equation of state of dense baryonic matter inside the neutron star. We combine a realistic phenomenological equation of state at low...
Yi Wang
(Department of Engineering Physics, Tsinghua University)
16/08/2012, 16:00
Data taken over the last several years have demonstrated that the Relative Heavy Ion Collider (RHIC) has created dense and rapidly thermalizing matter. The next objective at RHIC is to study properties of this partonic matter in detail in terms of color degrees of freedom and the equation of state. The precise measurement of transverse momentum distributions of quarkonia at different...
Prof.
Yuanfang Wu
(Institute of Particle Physics, CCNU, wuhan China)
16/08/2012, 16:00
Higher cumulant ratios of conserved charges are suggested to be sensitive probe of QCD critical end point [1] in relativistic heavy ion collisions. Their behaviors at current relativistic heavy ion collisions are highly interested and studied intensively [2,3]. Before we draw the critical-like fluctuations from the measured higher cumulants, it is necessary to know what the contributions of...
Prof.
Yuanfang Wu
(Institute of Particle Physics, CCNU, Wuhan, China)
16/08/2012, 16:00
Higher moments of net-baryon are suggested to be sensitive probe of QCD critical end point [1] in relativistic heavy ion collisions. Their critical fluctuations are highly interesting and instructive for the exploration of QCD phase diagram from both theoretical and experimental sides.
According to the universality of critical behavior, the QCD critical end point, and the chiral phase...
Fiorella Fionda
(Universita e INFN (IT))
16/08/2012, 16:00
The measurement of J/psi production in proton-proton collisions at the LHC energy regime allows to test QCD calculations. In addition, it provides the necessary reference for the ALICE Pb-Pb program. ALICE collected proton-proton collisions at sqrt{s} = 7 and 2.76 TeV in 2010 and 2011.
In this talk, we present the latest results on J/psi production in proton-proton collisions, measured by...
Grazia Luparello
(NIKHEF (NL))
16/08/2012, 16:00
The ALICE experiment at the Large Hadron Collider (LHC) has been designed in order to characterize the quark gluon plasma (QGP) in high-energy heavy-ion collisions. D mesons are powerful probes of the medium since the charm quarks are produced at the early stage of the collision and experience its entire evolution. In particular, the anisotropy parameter $v_2$ of D mesons is sensitive to the...
Sandro Bjelogrlic
(University of Utrecht (NL))
16/08/2012, 16:00
Due to their relatively high mass, heavy-flavour quarks, produced in high-energy heavy-ion collisions, are sensitive probes of the interaction dynamics inside the hot and dense QCD matter.
Since heavy quarks are produced in pairs during the initial stage of the collision, before the formation of the QGP, the measurement of heavy-flavour hadron production provides profound information on the...
Chanaka De Silva
(Wayne State University)
16/08/2012, 16:00
Angular di-hadron correlation studies in Au+Au collisions at 200 GeV have revealed a nearisde elongated structure in delta eta. This is often referred to as the ridge, and was found to extend to delta eta 9 units at the LHC. Using preliminary STAR data [3], we discuss methods to decompose 2D di-hadron correlations in Au+Au 200 GeV collisions on the nearside. Our analysis is performed as a...
Christoph Herold
16/08/2012, 16:00
We study the nonequilibrium dynamics of a quark fluid coupled to a sigma field and a Polyakov loop near the QCD phase boundary. As the system evolves through the first order transition line, baryon density fluctuations are enhanced in comparison with an evolution through the crossover or the critical point.
Dr
Juergen Eschke
(GSI Helmholtzzentrum)
16/08/2012, 16:00
The Compressed Baryonic Matter (CBM) experiment will conduct a comprehensive research programme on nuclear matter at high net baryonic densities. The Silicon Tracking System (STS) is the central detector of the CBM experiment. Its task is the standalone trajectory reconstruction of the high multiplicities of charged particles originating from high-rate beam-target interactions. The detector...
Taku for the ALICE-FOCAL Collaboration Gunji
(University of Tokyo (JP))
16/08/2012, 16:00
The W+Si electromagntic sampling calorimeter has been proposed as one of the upgrade plans for the LHC-ALICE experiment.
The role of this calorimeter is to add capabilities to measure direct photons, pi0's and jets over full azimuth in a forward rapidity region (2.5
Tatsuya Chujo
(University of Tsukuba (JP))
16/08/2012, 16:00
A di-jet produced by a hard scattering of partons plays a vital role to characterize the properties of hot and dense QCD matter produced in Pb-Pb collisions at LHC. In particular, a di-jet is one of the key probes to look for a medium response due to a strong jet quenching effect, as reported by the CMS and ATLAS collaborations. In this analysis, we used the data collected by the ALICE...
Mr
Patrick Huck
(CCNU/LBNL)
16/08/2012, 16:00
In the years 2010/11, the Solenoidal Tracker At RHIC (STAR) conducted a Beam Energy Scan (BES) over a wide range of center-of-mass energies with the purpose of studying the properties of the Quark-Gluon-Plasma (QGP) as well as searching for the onset of deconfinement and the critical point of the QCD phase diagram. The installation of the Barrel Time-Of-Flight-Detector (TOF) has enabled STAR...
Mr
Florian Senzel
(Goethe-Universität Frankfurt)
16/08/2012, 16:00
Recent experimental data measured in \sqrt{s}=2.76 TeV Pb+Pb collisions by ATLAS and CMS showed a significant imbalance in the transverse momenta of the two reconstructed jets with the highest transverse momenta. This momentum imbalance is assumed to be caused by the different energy and momentum loss of the di-jets by scatterings within the created medium. To investigate this momentum loss we...
Antonio Uras
(Universite Claude Bernard-Lyon I (FR))
16/08/2012, 16:00
The ALICE experiment is dedicated to the study of the quark gluon plasma in heavy-ion collisions at the CERN LHC. The Muon Forward Tracker (MFT) is under consideration by the ALICE Experiment to be part of its programme of detectors upgrade to be installed during the LHC shutdown planned for 2018. The MFT is a silicon pixel detector added in the Muon Spectrometer acceptance ($2.5 < \eta < 4$)...
Ekaterina Retinskaya
(IPhT Saclay)
16/08/2012, 16:00
We present the first extraction of the recently-proposed rapidity-even directed flow observable v1, obtained from an analysis of published two-particle correlation data from the ALICE Collaboration. An accounting of the correlation due to the conservation of transverse momentum restores the factorization seen in all other Fourier harmonics and thus indicates that the remaining correlation...
Gyulnara Eyyubova
(University of Oslo (NO))
16/08/2012, 16:00
Directed flow, v1, is measured over a wide range of pseudo-rapidity, |eta|<5.1,
in Pb-Pb collisions at 2.76 TeV with ALICE at the LHC.
The results of v1 are reported as a function of the pseudo-rapidity and the
transverse momentum for different collision centrality classes.
Using the neutral spectator deflection at beam rapidity
we investigate both the rapidity asymmetric v1 which is...
Akihiko Monnai
(The University of Tokyo)
16/08/2012, 16:00
The first results of the heavy ion program at LHC [1] suggest that the near-perfect fluidity discovered at RHIC is a universal property of the quark-gluon plasma (QGP) above and around the crossover temperature. The recent developments in hydrodynamic studies take account of the effects of shear and bulk viscosities as well as fluctuations for the quantitative understanding of the hot medium....
Pasi Huovinen
(Johann Wolfgang Goethe-Universität)
16/08/2012, 16:00
In hydrodynamical modeling of the ultrarelativistic heavy-ion collisions the freeze-out is typically performed at a constant temperature. In this work we introduce a dynamical freeze-out criterion, which compares the hydrodynamical expansion rate with the pion scattering rate [1]. Previous studies [2] have shown that differences between constant temperature and dynamical freeze-out criteria...
Mr
Zhiming Li
(Institute of Particle Physics, CCNU, Wuhan, China)
16/08/2012, 16:00
Higher cumulants of baryon number are suggested to be good
probe of Critical Point of QCD phase transition in
relativistic heavy ion collisions [1]. However, since the
number of produced protons is still small at RHIC, it is
pointed out [2] that the statistical fluctuation is not
negligible, and should be subtracted from directly measured
cumulants. So the dynamical cumulant ratios are...
Mate Csanad
(for the TOTEM Collaboration)
16/08/2012, 16:00
The TOTEM experiment at LHC measured the differential cross-section of elastic p+p scattering at 7 TeV, with the help of Roman Pot detectors placed as close as seven times the transverse beam size from the outgoing beams [1]. Results indicate an initial exponential decrease of dsigma/dt, followed by a significant diffractive minimum at |t| = (0.53 +- 0.01(stat) +- 0.01(syst)) GeV**2. For large...
Hamza Berrehrah
(Subatech)
16/08/2012, 16:00
One of the most advocated probes of the quark gluon plasma (QGP) properties is the $J/\psi$ suppression. However, the comparison between experimental data and theoretical scenarios is still rather inconclusive, as several mechanisms might participate to explain the observed suppression (sequential suppression, dynamical or statistical recombination, formation time,...), not to mention the cold...
Monika Sharma
(Vanderbilt University (US))
16/08/2012, 16:00
The first measurements of the elliptic azimuthal anisotropy of neutral pions, pi0s, produced in 2.76 TeV PbPb collisions will be presented. The results are based on data collected by the CMS experiment during the 2010 LHC running period. The amplitudes of the second Fourier component (v2) of the pi0 azimuthal distributions are extracted using an event-plane technique. The values of v2 are...
Denise Aparecida Moreira De Godoy
(Universidade de Sao Paulo (BR))
16/08/2012, 16:00
Heavy quarks, charm and bottom, are produced in early stages of heavy-ion collisions. Propagating through the created matter they serve as a probe of the dynamics of the strongly-interacting, hot and dense plasma of quarks and gluons (QGP).
The transverse momentum dependence of the elliptic flow (v2) of heavy quarks is sensitive to the properties of the QGP.
A non-zero v2 of low transverse...
Carlos Perez Lara
(Nikhef, Utrecht University)
16/08/2012, 16:00
Anisotropic flow of identified particles provides important information about the properties of the matter created in a heavy-ion collisions.We report the elliptic flow of strange (K$^0_s$ $\Lambda$) and multi-strange ($\Xi$ $\Omega$) hadrons measured at mid rapidity (|eta|<0.8) in Pb-Pb collisions at $\sqrt{s_{NN}}=2.76$ TeV. The results are compared to measurements at RHIC energies and...
Maja Katarzyna Mackowiak-Pawlowska
(Johann-Wolfgang-Goethe Univ. (DE))
16/08/2012, 16:00
NA61/SHINE at the CERN SPS is a fixed-target experiment pursuing a
rich physics program including measurements for heavy ion, neutrino and
cosmic ray physics.
The main goal of the ion program is to explore the most interesting region of the phase diagram of strongly interacting matter. Within the expected (T - mu_B) interval we plan to study the properties of the onset of deconfinement and...
Dr
Anar Rustamov
(Frankfurt University)
16/08/2012, 16:00
The study of event-by-event (e-by-e) fluctuations of chemical (particle-type) composition in high-energy nucleus-nucleus collisions is a helpful tool to pin-down the properties of strongly interacting matter. Indeed, according to theoretical calculations, the QCD critical point may be signalled by a characteristic pattern in the measured fluctuations. On the other hand, an incomplete particle...
Prof.
Ricardo Rodriguez
(Ave Maria University)
16/08/2012, 16:00
We investigate the possibility of enhanced jet quenching in the vicinity of the critical temperature similar to the scenario proposed by Liao and Shuryak [PRL 102, 202302(2009)]. We discuss the consequences of the fact that the "shells" of such enhanced, critical quenching grow thinner as a function of the center-of-mass energy sqrt(s) of the collision. A systematic scan of jet quenching as a...
Hideaki Iida
(Kyoto University)
16/08/2012, 16:00
Possible thermalization mechanism in heavy-ion collisions is explored in classical
Yang-Mills(CYM) theory with the initial condition of color-glass condensate
with noise varied. We calculate the Lyapunov exponents and show that even a tiny noise
triggers instability of the system and then a chaotic behavior sets in as described
by the positive Lyapunov exponents, or Kolmogorov-Sinai(K-S)...
Dr
Takashi Hachiya
(RIKEN)
16/08/2012, 16:00
The production of heavy quarks is a powerful tool for investigating
the dense partonic medium created in high energy heavy ion collisions.
Due to their large masses, heavy quarks are mainly produced
at the initial stage of the collisions.
Therefore the heavy quark probes is sensitive to the full time evolution
of the heavy ion collision.
The PHENIX experiment measured the strong flow...
Anthony Robert Timmins
(University of Houston (US))
16/08/2012, 16:00
The large multiplicities at the LHC permit flow harmonics to be determined on an event by event basis in Pb+Pb collisions. We extract these harmonics from inclusive event by event di-hadron correlations, where the minimum track pT is larger than 0.15 GeV. Within a fine centrality bin, we find the correlation function varies substantially on an event by event basis, indicating large...
Dr
Harri Niemi
(University of Jyväskylä, Department of Physics)
16/08/2012, 16:00
Nowadays, relativistic dissipative fluid dynamics is a common tool to
describe the space-time evolution of the quark-gluon plasma (QGP)
created in ultrarelativistic heavy-ion collisions. The validity of the fluid-dynamical approach is experimentally confirmed by the fact that
initial-state anisotropies are directly converted into nonvanishing
(event-averaged) Fourier coefficients $\langle...
Koichi Murase
(The University of Tokyo)
16/08/2012, 16:00
To investigate the physics of the strongly interacting system of quarks
and gluons under extreme conditions, heavy-ion collision experiments are
performed at Large Hadron Collider (LHC) and Relativistic Heavy Ion
Collider (RHIC). One of the major discoveries is that elliptic flow v_2
was comparable with an ideal hydrodynamic prediction and, as a result,
that a new paradigm of strongly...
Xu-Guang Huang
(Institute for Theoretical Physics)
16/08/2012, 16:00
We compute the electromagnetic fields generated in heavy-ion collisions by using the HIJING model. Although after averaging over many events only the magnetic field perpendicular to the reaction plane is sizable, we find very strong electric and magnetic fields both parallel and perpendicular to the reaction plane on the event-by-event basis. We study the time evolution and the spatial...
Stefan Thomas Heckel
(Johann-Wolfgang-Goethe Univ. (DE))
16/08/2012, 16:00
Results on event-by-event fluctuations of the mean transverse momentum of charged particles measured by the ALICE experiment at the LHC are compared to different Monte Carlo approaches. For these studies pp collisions at $\sqrt{s}$~=~0.9, 2.76 and 7~TeV and Pb--Pb collisions at $\sqrt{s_{\rm NN}}$~=~2.76~TeV are used. The analysis is performed within $|\eta| < 0.8$ and $0.15 < p_{\rm T} < 2...
Christoph Mayer
(Polish Academy of Sciences (PL))
16/08/2012, 16:00
The strong electromagnetic fields generated in the collision of Pb ions at the LHC allow photon-photon and photonuclear interactions to be studied in a kinematic regime unexplored so far. The exclusive photoproduction of vector mesons was studied with the ALICE detector in ultra-peripheral PbPb collisions, where the impact parameter is larger than the sum of the nuclear radii and hadronic...
Kouji Kashiwa
(RIKEN BNL Research Center)
16/08/2012, 16:00
We investigate the nontrivial correlation between the chiral and deconfinement transition in the two-color QCD.
To extract the information, the imaginary chemical potential is taken into account.
At $\theta = \pi/2$ where $\theta$ is the imaginary chemical potential divided by the temperature, there is the exact nontrivial center symmetry which is the $Z_2$ symmetry and this symmetry can be...
Philipe Mota
(Goethe Universität Frankfurt)
16/08/2012, 16:00
In this work, we propose a new
ow correlation observable that provide
valuable information about the geometrical properties of the QGP at the
thermalization time. An event-by-event analysis within a longitudinal tube
initial condition model shows that emitted particles high pt higher than 1
GeV are extremely sensitive to the level of granularity present in the initial
conditions....
354.
Fluctuating Hydrodynamics Confronts the Rapidity Dependence of Transverse Momentum Fluctuations
Sean Gavin
(Wayne State University)
16/08/2012, 16:00
Interest in the development of the theory of fluctuating hydrodynamics is growing [1]. Early efforts suggested that viscous diffusion broadens the rapidity dependence of transverse momentum correlations [2]. That work stimulated an experimental analysis by STAR [3]. We attack this new data along two fronts. First, we compute STAR’s fluctuation observable using the NeXSPheRIO code, which...
Taku Gunji
(University of Tokyo (JP))
16/08/2012, 16:00
We report on the new design of a forward electromagnetic calorimeter (FoCal) to be placed in the pseudorapidity region of $2.5 < \eta < 4.5$, which is under consideration as an upgrade of the ALICE experiment at the CERN-LHC. The physics goals of including the calorimeter in the forward direction are to study outstanding fundamental QCD problems at low Bjorken-x values, such as parton...
Dr
Sascha Vogel
(Frankfurt Institute for Advanced Studies)
16/08/2012, 16:00
One of the fundamental objectives of experiments with ultra-relativistic heavy ions is the study of hadronic matter at high density and high temperature. In this investigation we study in particular the information which can be obtained by analyzing baryonic and mesonic resonances in both hadronic and leptonic decay channels. The decay products of these resonances carry information on the...
Dr
Aneta Iordanova
(University of California, Riverside)
16/08/2012, 16:00
One important theoretical model of heavy ion collisions expects that the collision zone can be divided into two distinct regions: the core and the corona. The corona region is a low density p+p or p+A like region which may be a more favorable for J/psi production as opposed to the hot, dense core. From a Glauber model, this region is found to be symmetric about the reaction plane in Au+Au...
Elena Petreska
(Graduate Center/Baruch College CUNY)
16/08/2012, 16:00
A scaling law for the multiplicity distribution in high-energy hadronic collisions has been proposed by Koba, Nielsen, and Olesen (KNO). Experiments at the LHC observed that multiplicities in the central region of proton-proton collisions follow a negative binomial distribution and that they do exhibit KNO scaling. The negative binomial distribution has been theoretically reproduced in the...
Paul Hohler
(Texas A&M University)
16/08/2012, 16:00
The medium modifications of vector and axial-vector spectral functions are investigated using Weinberg and QCD sum rules in an attempt to establish chiral symmetry restoration. Such a study is essential for the interpretation of a pertinent signal from dilepton data in heavy-ion collisions. We start from vacuum spectral functions which include both ground- and excited-state resonances for both...
Oliver Fochler
(Goethe-Universität Frankfurt)
16/08/2012, 16:00
We present fully dynamic simulations of central and non-central heavy ion collisions at LHC and at RHIC energies within the perturbative QCD-based partonic transport model BAMPS (Boltzmann Approach to Multi-Parton Scatterings). We focus on the simultaneous investigation of bulk properties, such as elliptic flow, viscosity and thermalization, and of high-pT observables, such as jet...
Prof.
Masayuki Asakawa
(Osaka University)
16/08/2012, 16:00
We explore the relation between proton and nucleon numberfluctuations in the final state in relativistic heavy ion collisions. It is shown that the correlations between the isospins of nucleons in the final state are almost negligible over a wide range of collision energy. This leads to a factorization of the distribution function of the proton, neutron, and their antiparticles in the final...
Daisuke Watanabe
(University of Tsukuba (JP))
16/08/2012, 16:00
Heavy-ion experiments at the highest beam energy in the world (Pb-Pb at sqrt(s_NN) = 2.76 TeV) have started in 2010 at the Large Hadron Collider (LHC) at CERN. At the LHC, jet production is more abundant than at RHIC. Jet measurements play a critical role not only for probing the hot and high energy density matter in heavy ion collisions through parton energy loss, but also to observe possible...
Dr
Edouard Kistenev
(Brookhaven National Laboratory)
16/08/2012, 16:00
The RHIC physics programs will benefit from developments in hadronic calorimetry. Hadronic calorimetry serves to identify and characterize jets in p+p and A+A collisions and enables studies of the mechanisms of partonic energy dissipation in the medium at high densities and temperatures. The sPHENIX detector concept requires development of a hadronic calorimeter with fairly high sampling...
Dmitri Kotchetkov
(Ohio University (US))
16/08/2012, 16:00
The PHENIX detector was designed and built at the Relativistic Heavy Ion Collider to explore matter created in collisions of heavy nuclei. PHENIX, as an infrastructure of technologically different systems, has been recording data since 2000. Research results by the PHENIX experiment have already made an impact on the broad field of
experimental nuclear physics. Being in its second decade of...
Mr
Philip Rau
(Goethe University Frankfurt, Germany)
16/08/2012, 16:00
With an effective hadronic chiral flavor SU(3) model we investigate properties of QCD matter for a wide range of temperatures and baryochemical potentials. With our model, including all hadronic resonances up to masses of 2.6 GeV, we show that the strengths of the resonance couplings to the attractive scalar and the repulsive vector fields have a major impact on the order and location of the...
Francesco Becattini
(Unversity of Florence)
, Mr
Tim Schuster
(Yale University (US))
16/08/2012, 16:00
We analyze hadrochemical freeze-out in central Pb+Pb collisions at CERN
SPS energies, employing the hybrid version of the Ultrarelativistic
Quantum Molecular Dynamics model, which describes the transition from a
hydrodynamic stage to hadrons by the Cooper-Frye mechanism, and matches
to a final hadron-resonance cascade. We fit the results both before and
after the cascade stage using the...
George Moschelli
(Frankfurt Institute for Advanced Studies)
16/08/2012, 16:00
We show that initial state fluctuations in concert with later-stage hydrodynamic flow describes a range of observables including both even and odd flow harmonics, the ridge, and multiplicity, momentum and flow fluctuations [1]. This is the first comparison between multiplicity and transverse momentum fluctuations and flow fluctuations in the same framework. The simultaneous investigation of...
Alex Mwai
(Stony Brook University)
16/08/2012, 16:00
HBT measurements are sensitive to the expansion dynamics of the system and they can provide information on the size of the source in space and time at freeze-out (hadron decoupling). Previously, the size of the region of homogeneity has been shown to have an almost linear dependence with particle multiplicity at different beam collision energies. A question of interest is whether the same...
Gunnar Gräf
(Frankfurt Institute for Advanced Studies)
16/08/2012, 16:00
We use the Ultra-relativistic Quantum Molecular Dynamics (UrQMD) to explore HBT/Femtoscopic correlation in proton-proton and heavy ion collisions up to LHC energies. We discuss a) the scaling of HBT radii in proton-proton reactions at top LHC energies and b) the scaling of HBT radii from proton-proton to heavy-ion reactions from RHIC-BES to LHC energies for various systems.
[1] G. Graef et...
Dr
Daniel Kikola
(Purdue University)
16/08/2012, 16:00
Heavy quarks (charm and bottom) are produced early in the collisions and therefore are important probes of the hot and dense matter created in the reactions at RHIC energies. Electrons from semileptonic decays of heavy flavour mesons (so called non-photonic electrons, NPE) are the most feasible tool so far for studying heavy quarks in-medium interactions. NPE azimuthal anisotropy, $v_2$, is of...
Dr
Sascha Vogel
(Frankfurt Institute for Advances Studies)
16/08/2012, 16:00
One of the most promising probes to study deconfined matter created in high energy nuclear collisions is the energy loss of (heavy) quarks. It has been shown in experiments at the Relativistic Heavy Ion Collider that even charm and bottom quarks, despite their high mass, experience a remarkable medium suppression in the Quark Gluon Plasma.
In this investigation we study the energy loss...
Sanghoon Lim
(Yonsei University)
16/08/2012, 16:00
The measurement of single muons from the semi-leptonic decay of D and B mesons is a well-developed method for the study of heavy quark production at forward rapidity. Previous PHENIX results from p+p and Cu+Cu collisions at sqrt(s) = 200 GeV have reported the suppression of heavy quark production in central Cu+Cu collisions at rapidity = 1.65. The measurement of heavy quark production at...
Mr
Nirupam Dutta
(Doctoral Student, Bielefeld University)
16/08/2012, 16:00
In static picture a quarkonium bound state in deconfined medium is either completely dissociated above some threshold temperature or just stays in the specific state below the threshold. In contrast, some recent studies suggest that the static quark antiquark potential for describing bound quarkonia should include an imaginary part. This shows a finite life time of the bound state in the medium...
Dr
Hendrik van Hees
(Goethe University Frankfurt)
16/08/2012, 16:00
Heavy charm and bottom quarks provide an important probe of the
transport properties of the quark-gluon plasma, created in heavy-ion
collisions at the Large Hadron Collider (LHC). They are produced in the
early hard collisions and then interact with the hot and dense medium,
consisting of light quarks and gluons, undergoing a phase transition to
a hot and dense hadron gas. Using a hybrid...
Prof.
Feng Liu
() College of Physical Science and Technology, Central China Normal University, Wuhan, 430079, China)
16/08/2012, 16:00
One of the most exciting goals for the field of high-energy nuclear collisions is to understand the phase structure of matter with partonic degrees of freedom especially the transition from hadronic phase to partonic phase, the quark-gluon plasma (QGP). It is believed that the QGP phase dominates the evolution briefly during the early time of the Universe. In high-energy nuclear collisions at...
Jan Cepila
(Czech Technical University (CZ))
16/08/2012, 16:00
We discuss a production of direct photons at large transverse momenta p_T in nuclear collisions at different energies and rapidities corresponding to RHIC and LHC experiments. Direct photons are very convenient tool for investigation of nuclear effects since
they are not expected to be accompanied by any final state interaction, either energy loss or absorption. Therefore, besides the Cronin...
Norbert Novitzky
(Helsinki Institute of Physics (FI))
16/08/2012, 16:00
Neutral-pion spectra were measured at midrapidity ($|y|<0.35$) in
AuAu collisions at sqrt{sNN} = 39 and 62.4 GeV and compared to
earlier measurements at 200 GeV in the $1
amal sarkar
(Indian Institute of Technology, Mumbai)
16/08/2012, 16:00
The Relativistic Heavy-Ion Collider (RHIC) , at BNL, has started its beam energy scan program by colliding high energy heavy-ions corresponding to baryonic chemical potentials within the range of 20 - 550 MeV. One of the main goals of this beam energy scan program is to locate the critical point which is postulated to lie at the end of the phase transition boundary between...
NIHAR R SAHOO
(Variable Energy Cyclotron Centre)
16/08/2012, 16:00
To prob e the critical p oint (CP) of QCD phase transition, the Relativistic Heavy-Ion Collider (RHIC) at Brookhaven National Laboratory has
undertaken the beam energy scan program, colliding high energy heavy-ions
corresponding to baryonic chemical potentials within the range of 20 - 550
MeV. QCD based model calculations reveal that the correlation length of the
system diverges at the CP....
Rone Andrade
(Universidade de São Paulo USP)
16/08/2012, 16:00
In this work we study how highly energetic jets affect the hydrodynamic evolution of the quark-gluon plasma in an event-by-event basis. This is done by the introduction of a source term [1] in the energy-momentum conservation equation that describes the evolution of inviscid hydrodynamics (with a realistic equation of state [2]). The source is parametrized in terms of the direction of the jet...
Guang-You Qin
(Duke University/Wayne State University)
16/08/2012, 16:00
Jets propagating through dense matter are modified due to the scattering between the patrons of the jet with the constituents of the medium. Such scattering leads to an exchange of momenta between the medium and the jet, and has components that are both parallel and perpendicular to the direction of jet propagation. These scatterings introduce both drag and diffusion, and also change the rate...
Dr
Jan Steinheimer-Froschauer
(Lawrence Berkeley National Laboratory)
16/08/2012, 16:00
Using hydrodynamics we explore the effects of the initial state,
baryon stopping and baryon number transport on various observables such
as spectra, elliptic flow and particle yields for heavy ion collisions
at beam energies from sqrt{s_{NN}}=7.7 to 200 GeV. We find that
observed phenomena such as the centrality dependent freeze out
parameters as well as the apparent difference in...
Matthew Donald Steinpreis
(Ohio State University (US))
16/08/2012, 16:00
Femtoscopic correlations allow one to measure the space-time characteristics of particle production thanks to the effects of quantum statistics for identical particles and final state interactions for both identical and non-identical particles. The main features of the femtoscopy measurements in heavy-ion collisions from SPS to RHIC and LHC are i) the increase of the correlation radii with...
Jonathan Bouchet
(Kent State University)
,
Joseph Vanfossen
(Kent State University)
16/08/2012, 16:00
Heavy flavor particles, due to their production at the early stages of a collision, are of interest to study the properties of the matter created in heavy ion collisions at RHIC. Previous measurements of $D$ and $B$ mesons at RHIC[1, 2] using semi-leptonic probes show a suppression similar to that of light quarks, which is in contradiction with theoretical models including only a gluon...
Prof.
Ramona Vogt
(LLNL and UC Davis)
16/08/2012, 16:00
We assess the theoretical uncertainties on the inclusive $J/\psi$ production
cross section in the Color Evaporation Model using values for the charm quark
mass, renormalization and factorization scales obtained
from a fit to the charm production data [1]. We use our new results to provide
improved baseline comparison calculations at RHIC.
We also study the rapidity, $p_T$ and...
Liliana Apolinário
(Universidade de Santiago de Compostela)
16/08/2012, 16:00
In order to get information about the characteristics of the medium produced in high-energy heavy-ion collisions using reconstructed jets, the effect of background subtraction has to be well under control. In this study, we address this issue by embedding jets in a heavy-ion event and then considering the influence of the subtraction method and of different backgrounds, characterized by...
Dr
Sascha Vogel
(Frankfurt Institute for Advanced Studies)
16/08/2012, 16:00
One of the most promising probes to study deconfined matter created in high energy nuclear collisions is the energy loss of (heavy) quarks. Theoretically however there exist various ambiguities, which still need to be resolved. In this work we investigate the dependence on the medium description of heavy quark energy loss. We find that by only changing the theoretical medium description and...
Prof.
Toshitaka Tatsumi
(Department of Physics, Kyoto University)
16/08/2012, 16:00
Recently there has been much discussed the appearance of inhomogeneous chiral phases in the vicinity of the chiral restoration [1,2]. The critical end point should be the Lifshitz point, which properties have not been explored so much.Here we discuss an implication of inhomogeneous phase on cooling of hybrid stars.
We consider the dual-chiral-density-wave (DCDW) specified by the spatially...
Ioannis Bouras
(University of Frankfurt a.M.)
16/08/2012, 16:00
The initial conditions play a fundamental role in the fluid-dynamical modeling of the quark-gluon plasma (QGP) created in ultrarelativistic heavy-ion collisions. Many observables that are important in determining the properties of the QGP, such
as elliptic flow (v2) and triangular flow (v3), appear to be generated mainly from the initial geometry of the energy density profile. Since the...
Dr
Cesar L. for the PHENIX Collaboration Silva
(Los Alamos National Lab)
16/08/2012, 16:00
The hydrodynamic behavior of the strongly interacting Quark-Gluon Plasma (QGP) has mostly been studied at mid-rapidity and important additional constraints on the longitudinal expansion of the medium
are needed, in particular to help in constraining the initial state. The forward rapidity bulk medium initial state is also sensitive to low-x partons in one nucleus and high-x partons in the...
Kenta Shigaki
(Hiroshima University (JP))
16/08/2012, 16:00
A very intense magnetic field is expected in non-central nucleus-nucleus collisions, and to reach ~ 10^14 T at the LHC energies. Not only being the strongest magnetic field in the Universe (cf. ~ 10^11 T on the surface of magnetars), various consequences of physics interests are in discussion, including chiral magnetic effects, synchrotron radiation, and non-linear behaviors of QED e.g....
Mr
L. Chanaka De Silva
(University of Houston)
16/08/2012, 16:00
Triggered di-hadron correlation studies using Au+Au collisions at #sqrt(S_{NN}) = 200GeV in STAR revealed a novel “ridge-like” structure in two dimensions (#Delta#eta, #Delta#phi) [1] for high p_{T} particles. Similar structure was also present in an inclusive un-triggered di-hadron correlation analysis [2]. We study the <p_{T}> evolution of un-triggered analysis by increasing the lower p_{T}...
Prof.
Tomoki Endo
(Division of Physics, Department of General Education, Kagawa National College of Technology, Japan.)
16/08/2012, 16:00
Quark matter is expected in the core region of neutron stars because of the central density is sufficiently high for nucleons to dissolve into quarks. The compact stars consist of not only nuclear matter but also hypeons and quarks, we call such stars "hybrid stars". However, the equation of state (EOS) is still not clear and many theoretical studies try to elucidate the EOS in the high...
Mauro Rogerio Cosentino
(Lawrence Berkeley National Lab. (US))
16/08/2012, 16:00
Photons are of great interest in relativistic heavy-ion collisions due to the fact that they
do not interact strongly, and thus are used to make a tomographic view of those collisions.
Of special interest are the directly produced high-transverse momentum photons.
The ratio of their yield in Pb-Pb to pp collisions is sensitive to initial state effects.
Furthermore, direct photons can...
Marcel Araujo Silva Figueredo
(Universidade de Sao Paulo (BR))
16/08/2012, 16:00
J/psi measurements can be performed with ALICE through the dilepton decay into electrons (for rapidity |y|<0.9) and muons (for rapidity -4.0
Thomas Lang
16/08/2012, 16:00
We study charmonium physics in heavy-ion collisions within the framework
of the non-equilibrium transport model UrQMD at SPS, RHIC and LHC energies.
For pp collisions at LHC energies we find a considerable J/Psi suppression
in dependence of the particle multiplicity.
Michal Vajzer
(Acad. of Sciences of the Czech Rep. (CZ))
16/08/2012, 16:00
Collimated sprays of particles associated with hard partons, jets, are an important tool in testing QCD and probing the hot and dense nuclear matter created in high energy heavy-ion collisions. Jets enable to study hard scattering, fragmentation and hadronisation and their modification in presence of a partonic medium with respect to baseline vacuum measurements with proton-proton...
Ying Lu
(University of Maryland (US))
16/08/2012, 16:00
The poster presents the jet response and inclusive pT spectra of jets reconstructed in PbPb collisions with the CMS detector at a center-of-mass energy of 2.76 TeV. The jets are found and reconstructed using both the calorimeters and the tracker system, through iterative cone and anti-kT algorithms, separately. The high-pT jet triggers and their efficiencies are studied for both PbPb and pp...
Dosatsu Sakata
(University of Tsukuba (JP))
16/08/2012, 16:00
In heavy-ion collisions, jet properties are expected to be modified by the interaction with the hot and dense medium. The modification is strongly related with properties of hot and dense matter and the study of jet properties is a versatile probe for the properties of the QGP.
However, in heavy-ion collisions it is difficult to recover the jet quenching effects at small particle momentum due...
Pengfei Zhuang
(Tsinghua University)
16/08/2012, 16:00
Different from the Jpsi yield which is almost identical at SPS, RHIC and LHC energies, the Jpsi transverse momentum distribution is sensitive to the nature of the medium and can be used to probe the quark-gluon plasma formation in heavy ion collisions. We calculated in a detailed transport approach the nuclear modification factor as a function of transverse momentum, the averaged transverse...
Hua Pei
(University of Illinois at Chicago)
16/08/2012, 16:00
Angular correlations with respect to a back-to-back trigger pair of high-p_T hadrons with similar momenta (above 4 GeV/c) have shown no differences between d+Au and Au+Au collisions suggesting tangential emission of selected di-jets. In this talk we increase the p_T threshold of the leading hadron in the pair (8, 10 and 12 GeV/c) to vary the degree of the surface bias. The di-jet energy...
Akira Ohnishi
(Kyoto University)
16/08/2012, 16:00
We study Lambda-Lambda correlation in high-energy heavy-ion collisions based on the Lambda-Lambda interactions proposed so far. Lambda-Lambda interaction and the existence of H-dibaryon are long-standing problems in hadron physics. Since high-energy heavy-ion collisions at RHIC and LHC can be utilized as the exotic hadron factories [1], they would also provide information on exotic...
W.J. Llope
(Rice University)
16/08/2012, 16:00
In the dense and high-temperature systems formed in relativistic
heavy-ion collisions, final-state composites - light nuclei and
antinuclei - are formed close to the freeze-out hypersurface. Their
spectra, compared to those of the constituent (anti)nucleons, can be
described by picturing the formation process as the coalescence of a
number of nucleons that are close to each other in phase...
Sudipan De
(Department of Atomic Energy (IN))
16/08/2012, 16:00
Multiple parton interactions are expected to produce large long-range multiplicity correlations in high energy proton-proton and nucleus-nucleus collisions. Color glass condensate models explain the long range forward-backward (F-B) correlations by introducing strong color fields extended longitudinally in rapidity. Clustering of color sources also leads to F-B correlations. The measurement of...
Dr
Huang Bingchu
(Brookhaven National Lab)
16/08/2012, 16:00
An enhancement of low-mass di-electron production which is compared to expected yields from known hadron sources was observed by the CERES experiment at CERN SPS in 158 A GeV central Pb+Au collisions
(sqrt(s)=17.3GeV). More recently, NA60 reported their di-muon
measurements in 158 A GeV In+In collisions. The enhancement of di-muon at $M_{\mu\mu} < 1$ GeV/$c^{2}$ can be described by a...
Emilia Leogrande
(Universita e INFN (IT))
16/08/2012, 16:00
Luminosity is an essential ingredient for the measurement of the cross section of physical processes. Luminosity determination in ALICE at the LHC is based on the visible cross sections measured in dedicated calibration experiments (van der Meer scans).
Besides serving as reference for the determination of integrated luminosities, the cross sections measured in van der Meer scans can, with...
Edward Shuryak
(stony brook university)
16/08/2012, 16:00
Confinement phenomenon for a long time was associated with
Bose-Einstein condensation (BEC) of cirtain magnetic objects.
In a series of previous works we had shown that it is indeed the
case for lattice monopoles, which in pure gauge theory are about
as numeroous near $T_c$ as gluons. We can now show that with
increasing number of quark flavors to $N_f\sim 10$ the...
Ryohji (for the PHENIX collaboration) Akimoto
(University of Tokyo)
16/08/2012, 16:00
Heavy quarks (charms and bottoms) are interesting probes with which to study the properties of quark gluon plasma (QGP). Heavy quarks are created by initial hard scatterings, and thus are good probe to investigate the full time evolution of heavy ion collisions. Due to their heavy mass, the energy loss within the QGP is expected to be different for heavy quarks than for light quarks....
Shawn Whitaker
(Iowa State University)
16/08/2012, 16:00
The suppression of quarkonia in heavy ion collisions has long been thought to provide an indication of the temperature dependent Debye screening length of color charge in the quark gluon plasma. A large sample of Au+Au collisions at $\sqrt{s_{NN}}$=200 GeV have been collected by PHENIX in 2010. Using the PHENIX measurement of Upsilon production in p+p collisions as a reference, we will present...
Zubayer Ahammed
(Department of Atomic Energy (IN))
16/08/2012, 16:00
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\title{Measurement of energy...
Christoph Baumann
(Johann-Wolfgang-Goethe Univ. (DE))
,
Markus Kohler
(GSI - Helmholtzzentrum fur Schwerionenforschung GmbH (DE))
16/08/2012, 16:00
Direct photons are an important probe of the hot and dense medium created in heavy-ion collisions because they do not interact with the medium and therefore carry information of all stages of the collision.
At low momenta, thermal emission, which would provide the ideal measurement of temperature of the quark-gluon plasma, is expected to dominate over other sources of direct photons. However,...
Satyajit Jena
(IIT- Indian Institute of Technology (IN))
16/08/2012, 16:00
Charge fluctuations are considered to provide a possible signature for the existence of the de-confined Quark Gluon Plasma phase (QGP). Charge fluctuations are sensitive to the number of charges in the system, thus the fluctuations in the QGP, with fractionally charged partons, are significantly different from those of hadron gas with unit charged particles. The study of charge fluctuations...
Satoshi Yano
(Hiroshima University (JP))
16/08/2012, 16:00
The $\omega$ meson is a promising probe to investigate the properties of the QGP. It is well known that the yield of high-p_t particles is suppressed in nucleus-nucleus collisions relative to that in pp collisions.
The effect is attributed to the energy loss of the energetic parent partons traversing the created medium.
Since $\pi^0$ and $\omega$ mesons have the same quark content (u and d),...
Tomasz Bold
(AGH Univ. of Science amp; Technology, Krakow)
16/08/2012, 16:00
The results of the study of ultraperipheral (gamma-gamma and gamma-Pomeron) interactions are presented. The analysis was performed with the data recorded by the ATLAS experiment during LHC Pb-Pb run in year 2011. The data, taken at the beam energy of 2.75 TeV per nucleon, correspond to an integrated luminosity of 141/microbarn. Muon pairs, produced in pure electromagnetic two-photon...
Bernard Richard Hicks
(Yale University (US))
16/08/2012, 16:00
Heavy quarks, being produced in the initial stages of heavy-ion collisions, provide an excellent probe for the properties of the quark-gluon plasma (QGP). The expected in-medium energy loss of quarks is predicted to have a mass-dependence; however, recent results indicate that heavy-quarks lose more energy than expected. The measurement of electrons from heavy flavor decays provides insight...
326.
Measurements of anisotropic flow($v_n$, n=1,2,3,4) in Cu + Au collisions at 200 GeV from PHENIX
Dr
shengli huang
(PHENIX Collaboration)
16/08/2012, 16:00
Measurements of the anisotropic flow with different order harmonic
coefficients ($v_n$, n=1,2,3,4) have played a pivotal role in the
discovery of the strongly coupled quark-gluon plasma (sQGP) at
RHIC. They are also important for the study of the viscous
hydrodynamics and the extraction of the shear viscosity over
entropy density ($\eta/s$). The anisotropic flow is strongly
coupled with...
Sidharth Kumar Prasad
(Wayne State University (US))
16/08/2012, 16:00
We present results of a study of charged particle jet properties in pp
collisions at $\sqrt{s}$ = 7 TeV using the ALICE detector.
Jets are reconstructed using charged tracks at mid-rapidity with the
anti-$\rm k_{t}$ [1] jet finding algorithm from FastJet.
We will discuss the transverse momentum dependence of three jet
properties: charged particle multiplicity, jet size, and...
Rongrong Ma
(Yale University (US))
16/08/2012, 16:00
Jet properties are expected to be modified in the dense, colored medium formed in Pb-Pb collisions at the LHC. To quantify such modifications, the measurement of reference distributions in pp collisions is essential. Jets are reconstructed from charged tracks measured in the ALICE central barrel, as well as the neutral energy measured in the Electromagnetic Calorimeter (EMCal). In this poster,...
Szymon Mateusz Pulawski
(University of Silesia (PL))
16/08/2012, 16:00
Preliminary NA61/SHINE results on π+, π-, K+, K-, p and pbar spectra in p+p interactions at 20-158 GeV/c will be presented. NA61/SHINE at the CERN SPS is a fixed-target experiment pursuing a rich physics program [1]. Thanks to its large acceptance and excellent particle identification capability NA61/SHINE is well suited for performing high-precision particle production measurements in p+p,...
Karoly Uermoessy
(Hungarian Academy of Sciences (HU))
16/08/2012, 16:00
For the description of hadronic spectra in high-energy nuclear reactions, it is essential to understand the process of hadronisation. However, hadron creation is still an unsettled matter from the theoretical point of view.
In the talk, I show that hadron distributions inside jets (fragmentation functions) created in s^1/2 = 7 TeV (LHC) proton-proton [1] and also in high-energy...
Dr
Daniel Kikola
(Purdue University)
16/08/2012, 16:00
Anisotropic flow, which arises from correlations to the common collision geometry, is sensitive to the early stage of the expansion of the medium created in relativistic heavy-ion collisions. Azimuthal anisotropy is measured by final state particle correlations and is thus contaminated by correlations unrelated to the common geometry (nonflow). The contamination of nonflow hampers further...
Dr
Paul Stankus
(Oak Ridge National Lab)
16/08/2012, 16:00
The large majority of observations made of high-energy heavy-ion collisions at RHIC and LHC have been within a narrow range at mid-rapidity. These have been greatly informative, of course; but they've provided a window only onto a central "slice" of the created medium, leaving the full 3-D picture of the collision as a relatively unexplored frontier. How the initially locally thermalized...
Jussi Auvinen
(University of Jyväskylä)
16/08/2012, 16:00
A strong suppression of heavy-flavor hadrons has been seen in ultrarelativistic heavy ion collisions at BNL-RHIC and CERN-LHC. This surprising result has challenged the view of gluon radiation dominating over elastic 2-to-2 processes as a cause of parton energy loss in a quark-gluon plasma. To study the effectiveness of elastic collisions as the suppression mechanism in detail, we have...
Clint Young
(McGill University)
16/08/2012, 16:00
Jets have proven to be an important observable of heavy-ion collisions at the LHC; recent analysis has also made jets an important probe at RHIC energies as well. Unlike the spectrum of single hadrons, the spectrum of jets is highly sensitive to $\hat{q}_{\perp}$, as well as being sensitive to partonic energy loss and radiative processes. We use MARTINI, an event generator, to study how...
Prof.
Jens Jorgen Gaardhoje
(Niels Bohr Institute)
16/08/2012, 16:00
We discuss opportunities that may arise from subjecting high-multiplicity events in relativistic heavy ion collisions to an analysis similar to the one used in cosmology for the study of fluctuations of the Cosmic Microwave Background (CMB). To this end, we discuss examples of how pertinent features of heavy ion collisions including global characteristics, signatures of collective flow and...
Ms
Dronika Solanki
(University of rajasthan)
16/08/2012, 16:00
The main goal of the STAR experiment at Relativistic Heavy Ion Collider (RHIC) is to study the properties of the QCD matter at extremely high energy density and parton density, created in the heavy ion collisions. Photons are produced at all stages of the colliding system and through decay of produced particles like neutral pions. The multiplicity measurement of photons on an event-by-event...
Fengchu Zhou
(Central China Normal University (CN))
16/08/2012, 16:00
A central goal of the heavy-ion program at LHC is to study the properties of the quark-gluon plasma (QGP). The azimuthal anisotropy of particle production is a sensitive tool to study the features of the QGP. The anisotropy is typically characterized by $v_2$, the second harmonic coefficient of the Fourier series expansion of the particle azimuthal distribution with respect to the reaction...
Paraskevi Ganoti
(Oak Ridge National Laboratory - (US))
16/08/2012, 16:00
In this poster, $\pi^0$ and $\eta$ spectra in pp collisions at sqrt(s) = 7 TeV from the ALICE 2010 and 2011 runs (extended calorimeter acceptance) will be presented.
The neutral mesons are reconstructed via their two photon decay channel where both photons are measured with the ALICE EMCal. For the ALICE 2011 run both, minimum bias and EMCal triggered data, have been analyzed. A precise...
Mr
Matthias Drews
(Technische Universitaet Muenchen)
16/08/2012, 16:00
Recently a two-solar-mass neutron star was observed. This puts new constraints on effective models at zero temperature and high chemical potential. In our approach we include mesonic degrees of freedom as well as nucleons in the framework of the Functional Renormalization Group. In this way, fluctuations beyond the mean-field approximation are taken into account.
Gyulnara Eyyubova
(University of Oslo (NO))
16/08/2012, 16:00
Recently significant effort is made to study azimuthal flow asymmetries in ultra-relativistic heavy ion reactions. At finite impact parameters the directed flow and the elliptic flow were dominant observables for many years.
In head-on collisions there would be no reason to have an azimuthal or longitudinal asymmetry, nevertheless, new observations for the higher harmonics show [1] that...
Amaresh Jaiswal
(Tata Institute of Fundamental research, Mumbai)
16/08/2012, 16:00
Starting with the relativistic Boltzmann equation where the collision term is generalized to include nonlocal effects, and using Grad's 14-moment approximation for the single-particle distribution function, we derive equations for the relativistic dissipative fluid dynamics. We compare them with the corresponding equations obtained in the standard Israel-Stewart and related approaches. Our...
Mr
Risto Paatelainen
(University of Jyvaskyla, Finland)
16/08/2012, 16:00
The EKRT model [1] which combines pQCD minijet production with the saturation of produced gluons and (ideal) hydrodynamics, has predicted the measured multiplicities in central A + A collisions both at RHIC and LHC remarkably well [2]. Also the published pT spectra of bulk hadrons (at RHIC) have been reproduced quite nicely [3]. We now bring this closed framework to NLO as rigorously as...
Erike Cazaroto
(University of Sao Paulo)
16/08/2012, 16:00
At high energies the amount of gluons in a hadron is much larger than the amount of any other constituent, for example it is much larger than the amount of sea quarks. Therefore, at high energies the hadronic cross sections are basically a function only of the gluons distribution. The color dipole formalism applied to photon-photon collisions implies that, before interacting, each of the...
Dr
Min He
(Cyclotron Institute, Texas A&M University)
16/08/2012, 16:00
We compute open heavy-flavor (HF) transport in relativistic heavy-ion collisions by combining a strong-coupling treatment in both macro- and microscopic dynamics (hydro and nonperturbative diffusion interactions) [1]. The hydrodynamic bulk evolution is quantitatively constrained by bulk and multi-strange hadron spectra and elliptic flow [2]. In the Quark-Gluon Plasma (QGP) phase, heavy-quark...
Mauricio Martinez Guerrero
(Universidade de Santiago de Compostela)
16/08/2012, 16:00
Radiative interferences in the multiparton shower is the building block of QCD jet physics in vacuum. The presence of a QCD medium is expected to alter this interference pattern. We investigate color coherence effects in the medium modification to the initial state radiation in a simple setup which allows to include these effects in a clean way. We derive the medium induced gluon spectrum of...
Alexander Schmah
(Lawrence Berkeley National Lab)
16/08/2012, 16:00
The RHIC Beam Energy Scan covers a wide range in the QCD phase diagram temperature vs. baryon chemical potential. A phase transition between the Quark Gluon Plasma and the hadron gas phase is expected in this region of the QCD phase diagram. The elliptic flow $v_{2}$ is one of the observables which is sensitive to the pressure gradients in the initial stage of heavy-ion collisions. Hence it...
Anthony Robert Timmins
(University of Houston (US))
16/08/2012, 16:00
The large multiplicities at the LHC potentially permit azimuthal flow to be accurately determined on an event by event basis in heavy-ion collisions. I will discuss methods one can obtain full vn distributions from such measurements. In particular, any measurement of event-wise flow will be subject to statistical smearing, and I will review unfolding techniques to recover the true vn...
Fuming Liu
(Central China Normal University)
16/08/2012, 16:00
We will address the possibility of QGP formation in pp at 7TeV and 14 Tev with given life scan and size of QGP
based on quantitative model estimation and constrained with all available data at LHC from the four collaborations.
Then discuss the possible QGP signals in pp collisions, which certainly differ to the QGP signals in AA collisions.
To theoreticians: Most of you think QGP...
Tamal Kumar Mukherjee
(Institute of High Energy Physics, TPCSF)
16/08/2012, 16:00
We follow chiral effective model [1] of a quarkonia nonet and a tetraquark nonet as well as a complex iso-singlet (glueball) field to study the lowest lying scalar mesons on the basis of chiral symmetry and UA(1) symmetry. By virtue of the isospin symmetry, the isospin 1 and isospin 1/2 physical states are assumed to have two and four bare quark components whereas I = 0 physical scalar and...
Jan Uphoff
(Goethe University Frankfurt)
16/08/2012, 16:00
The production and space-time evolution of heavy quarks and J/psi in the quark gluon plasma is studied within the partonic transport model Boltzmann Approach to MultiParton Scatterings (BAMPS). An updated version of BAMPS is presented which allows interactions among all partons: gluons, light quarks and heavy quarks. Heavy quarks, in particular, interact with the rest of the medium via binary...
Mr
Hongxi Xing
(Institute of Particle Physics, Central China Normal University)
16/08/2012, 16:00
Within the framework of generalized collinear factorization in perturbative QCD (pQCD), we study the effect of initial multiple parton scattering and induced parton energy loss in Drell–Yan (DY) process in proton–nucleus collisions. We express the contribution from multiple parton scattering and induced radiative energy loss to the DY dilepton spectra in terms of nuclear modified effective...
Hidemitsu Asano
(Kyoto Univ.)
16/08/2012, 16:00
The PHENIX experiment at the Relativistic Heavy Ion Collider (RHIC) at
Brookhaven National Laboratory has been upgraded by installing a
Silicon Vertex Tracker (VTX). The VTX has been developed for heavy flavor (charm and bottom) measurements and dedicated to precise tracking of primary and secondary vertices. Resolution of primary vertex reconstruction and distance of closet approach (DCA)...
Libor Skoda
(Czech Technical University (CZ))
16/08/2012, 16:00
We present a performance study of a compact electromagnetic calorimeter meant to serve in a forward region (2 < eta < 4.5) in collider experiments in pp, pA and AA collisions. This kinematic region at LHC energies allows one to study very low Bjorken x physics. Measurement of direct photons in this region enables one to improve the precision of (nuclear) parton distribution functions.
Our...
Pilar Staig
(Stony Brook University)
16/08/2012, 16:00
We study the effect that perturbations and their propagation through the medium have in the final particle distributions of heavy ion collisions. Our work is constrained to central collisions only, where the medium can be described by the solution to conformally invariant hydrodynamics developed by Gubser and Yarom, which is a generalization of Bjorken flow where the boost-invariant medium...
Mr
Abhisek Sen
(Georgia State University)
16/08/2012, 16:00
$J/\psi$ production is considered as one of the very important probes for studying the properties of quark-gluon plasma (QGP). PHENIX observed a large suppression of $J/\psi$ production in Au+Au collisions at $\sqrt{s_{NN}}=$ 200 GeV in comparison with binary collision scaled p+p collisions. The level of this suppression is similar to that observed in other energies in CERN-SPS and LHC. ...
Antonio Uras
(Universite Claude Bernard-Lyon I (FR))
16/08/2012, 16:00
Strangeness production provides one of the key observables to characterize the hot and dense state of strongly interacting matter produced in high-energy nuclear collisions. To access this information, ALICE measured phi meson production both in proton-proton and Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV in the dimuon channel, in the rapidity region 2.5 < y < 4. Thanks to these measurements,...
Mr
Mukesh Mukesh Kumar Sharma
(University Of Jammu)
16/08/2012, 16:00
The study of phi meson and multi-strange production in heavy ion collision are the most interesting observables for exploring the new phase of matter named Quark Gluon Plasma. We will investigate the phi-meson and multi-strange production at FAIR energies using transport models like Ultra Relativistic Quantum Molecular Dynamics (UrQMD)[1] and A Multi Phase Transport Model (AMPT)[2]. The UrQMD...
Mr
Guangyao Chen
(Cyclotron Insitute and Department of Physics&Astronomy, Texas A&M University)
16/08/2012, 16:00
A new source of photon and dilepton emission from nuclear matter undergoing phase transition from partonic to hadronic degrees of freedom is studied. Electromagnetic radiation can be emitted when quark antiquark pairs recombine into pions and other hadrons. The photon and dilepton production rates are found to be comparable to those in quark gluon plasma and hadronic matter around the critical...
Dr
Martin Purschke
(BROOKHAVEN NATIONAL LABORATORY, for the PHENIX Collaboration)
16/08/2012, 16:00
The initial stage of the sPHENIX upgrade detector at RHIC will focus on the measurement of jet observables, such as gamma-jet properties, withhigh statistics over a large kinematic range. We have studied several key performance parameters of the envisioned electromagnetic calorimeter. In this poster we will present the studies of the photon identification in the presence of the particle...
Pat Kenny
(University of Kansas (US))
16/08/2012, 16:00
Ultra-peripheral collisions (UPCs) of heavy ions involve long range electromagnetic interactions at impact parameters larger than twice the nuclear radius. At TeV energies, the strong electromagnetic field due to the coherent action of the Z=82 proton charges generates a large flux of photons, which can be used for high-energy photoproduction studies. Heavy vector mesons (for example J/psi,...
Mr
Yan Yang
(Ohio State University)
16/08/2012, 16:00
Correlations between non-identical particles at low relative momentum
in the center of mass ($|\vec{k}^*|$) encode unique information on the
space-time structure of the emitting system. In addition to size of
the homogeneity region, analysis of correlation functions in the three-
dimensional $\vec{k}^*$ space can reveal a space-time offset of one
particle species (e.g. kaons) with respect...
Dr
Dilan Madagodahettige Don
(STAR (Creighton University))
16/08/2012, 16:00
Ultraperipheral collision events are effectively photoproduction on nuclear targets. These events provide an ideal proving ground for new programs in e+A physics. For the first time, STAR has collected a large enough sample of rho mesons to study their diffractive interaction with Au nuclear targets in detail. The transverse momentum distribution of rho mesons is sensitive not only to the...
Dr
Chin-Hao Chen
(PHENIX Collaboration)
16/08/2012, 16:00
Heavy flavor quarks such as charm and bottom, provide important probes of the parton energy loss mechanism in quark-gluon plasma. By studying the single electrons coming from the single leptonic decays of D and B mesons, we can study the energy loss of charm and bottom.
In order to study the heavy flavor energy loss process, a baseline comparison in p+p collisions where there is no...
Patrick Simon Reichelt
(Johann-Wolfgang-Goethe Univ. (DE))
16/08/2012, 16:00
The measurement of electron-positron pairs in the low invariant mass region allows to study the vacuum and in-medium properties of light vector mesons. Dielectrons also probe the production of thermal photons in heavy-ion collisions.
ALICE is well-suited to perform this measurement due to its excellent tracking and particle identification capabilities at very low momenta. However, Dalitz...
Dr
Zhi Qiu
(Ohio State University)
16/08/2012, 16:00
The Quark-Gluon Plasma (QGP) created in heavy-ion collisions is well described by viscous hydrodynamic simulations. A key QGP transport coefficient, its specific shear viscosity eta/s, can be extracted by comparing such simulations with experimental data. Previous extractions gave (eta/s)_QGP ~ (1-2.5)/(4\pi) where the ~100% uncertainty arises mainly from ambiguities in the initial fireball...
Yukinao Akamatsu
(Nagoya University)
16/08/2012, 16:00
Single heavy quark system has been considered as a hard probe for dynamical information of quark-gluon plasma (QGP), namely drag force, while heavy quarkonium has been thought to probe static information, such as heavy quark potential. However, this intuitive picture is not correct, in particular for the latter. Recent theoretical developments have shown that dynamical feature is also...
Kazuhiro Watanabe
(The University of Tokyo)
16/08/2012, 16:00
We study the parton saturation effects on heavy quark production
in proton-nucleus collisions at collider energies, using the CGC
formula proposed by Blaizot-Gelis-Venugopalan (Nucl.Phys.A743:57-91,2004).
Previously it was numerically evaluated using the unintegrated
gluon distribution from the McLerran-Venugopalan model including
the x-evolution effect with the Balitsky-Kovchegov...
Huichao Song
(The Ohio State University)
16/08/2012, 16:00
Viscous hydrodynamic calculations have shown that the quark-gluon plasma (QGP) shear viscosity can be extracted from elliptic and triangular flow data [1]. However, strong non-equilibrium effects, both in the chemical composition and the kinetic evolution, during the hadronic stage influence the development and distribution of flow anisotropy and must be correctly accounted for when extracting...
Marzia Rosati
(Iowa State University)
16/08/2012, 16:00
The PHENIX collaboration is in the process of developing an ambitious upgrade plan (called sPHENIX) to significantly improve physics capabilities and make use of the full enhanced luminosity at RHIC. The sPHENIX design contains silicon tracking, electromagnetic and hadronic calorimetry with large kinematic coverage and high data rate capabilities to sample 50 billion Au+Au collisions...
Mr
Deke Sun
(Purdue University)
16/08/2012, 16:00
There has been a lot of interest in testing radiative energy loss
calculations against data from RHIC and the LHC. It is customary, as in the Gyulassy-Levai-Vitev (GLV) approach, to formulate the energy loss of a jet parton as a line integral from the production point along a straight-line trajectory. Calculations then account for variations in path length with jet origin and direction, and...
Boris Tomasik
(Univerzita Mateja Bela (SK))
16/08/2012, 16:00
A Monte Carlo event generator REGGAE is presented which can generate momenta for given set of particles so that total energy and momentum assumes a pre-set value. The generator is proved to fill the available phase-space uniformly. In comparison to other algorithms it is considerably more effective in situations where many particles are produced and/or large part of the total energy is stored...
Prof.
Rolf Scharenberg
(Purdue University)
16/08/2012, 16:00
The major challenge in heavy ion physics is to extract the equation of state and the shear viscosity to entropy ratio $\eta/s$ from the data. In the clustering of color sources (CSPM) the charged particle transverse momentum spectrum is used to measure the percolation density parameter $\xi$, which determines the initial temperature T, energy density $\epsilon$, and the $\eta/s$ ratio versus T...
Koichi Murase
(The University of Tokyo)
16/08/2012, 16:00
To investigate the physics of the strongly interacting system of quarks
and gluons under extreme conditions, heavy-ion collision experiments are
performed at Large Hadron Collider (LHC) and Relativistic Heavy Ion
Collider (RHIC). One of the major discoveries was that elliptic flow v_2
was comparable with an ideal hydrodynamic prediction and, as a result,
that a new paradigm of strongly...
Martin Schulc
(Czech Technical University (CZ))
16/08/2012, 16:00
We perform (3+1)-dimensional ideal hydrodynamic calculation with source terms that describe energy and momentum deposition of hard partons in static quark-gluon plasma and study not only QGP response to one parton, but also interplay of perturbations due to two leading particles propagating in various directions. Energy deposition is described by a simple Bethe-Bloch model which leads to an...
385.
Results from Fixed-Target Collisions from STAR: Au+Al at $\root{S_{NN}}$ = 4.5, 3.5 and 3.0 GeV
Brooke Haag
(U)
16/08/2012, 16:00
The RHIC Beam Energy Scan (BES) was proposed to search for the
possible critical point and to study the nature of the phase transition between hadronic and partonic matter.
However, several dynamical model simulations (UrQMD, PHSD,
QGSM, GiBUU, 3-fluid) suggest that the partonic phase is entered for
center-of-mass collision energies as low as 4-5 GeV [1]. Collisions
between beam halo...
Dr
Supriya Das
(Bose Institute)
16/08/2012, 16:00
Recent data from LHC has revived the question whether the matter produced in high energy hadronic collisions is thermalized or not. With the published data from ALICE and CMS experiments, we have shown that the multi-particle production in p+p collisions at LHC energies available up to now, follows the scaling of information entropy if one takes the chaotic and coherent sources of particle...
Giorgio Torrieri
(JW Goethe Universitat, Frankfurt)
16/08/2012, 16:00
In this talk we show that azimuthal harmonics of hard particles, thought to be generated via parton energy loss, should scale differently w.r.t. multiplicity and system size to azimuthal harmonics of soft particles, thought to be generated by hydrodynamic response.
By scanning harmonics in both energy and system size, we obtain a way of determining the domain of validity of...
Prof.
Fotis Diakonos
(University of Athens, Physics Department, Section of Nuclear and Elementary Particle Physics, GR-15771)
,
Nikolaos Davis
(University of Athens (GR))
16/08/2012, 16:00
We perform factorial moment analysis in the transverse
momentum space of protons produced at midrapidity in A+A collisions at the NA49 experiment (SPS, CERN). After background subtraction we find power-law dependence of the correlator on the number of phase space cells for the systems Si+Si and Pb+Pb at 158A GeV with large values of the associated characteristic
exponent (intermittency...
Michal Petran
(Czech Technical University (CZ))
16/08/2012, 16:00
Soft hadron production at LHC energies presented a new challenge for the statistical hadronization mode (SHM). We show that the SHARE chemical nonequilibrium model describes well the available hadron yield data. We than extend SHARE to include CHARM contribution to hadron yields and present a remarkably accurate description of hadron yields at energy s_{NN} =2.76 TeV for several high ...
Dr
Nasser Demir
(Kuwait University)
16/08/2012, 16:00
We present a detailed comparison between two different methods to calculate
the shear viscosity coefficient for a set of four hadronic systems. One calculation
employs the Chapman-Enskog method to calculate the shear viscosity coefficient
for a hot hadronic system. The other calculation uses the Green-Kubo method
to calculate the shear viscosity for a hadronic medium simulated using
the...
101.
Signature of liquid-gas phase transition and critical behavior in projectile multifragmentation
Ms
Rupalim Talukdar
(Department of Physics, Gauhati University, India)
16/08/2012, 16:00
A high-statistics exclusive study of the multifragmentation of Mg-Em interaction at 4.5 AGeV has been performed to realize the critical behaviour. A number of relevant observables such as fluctuation in the sizes of the largest cluster, reduced variance and the mean value of second moment of charge distribution were estimated with the experimental data. The observed results are compared...
601.
Silicon pixel and strip detector development for the upgrade of the ALICE Inner Tracking System
Giacomo Contin
(Universita e INFN (IT))
16/08/2012, 16:00
The main physics motivation for the upgrade of the Inner Tracking System of the ALICE experiment is to perform new measurements on charm and beauty production in heavy-ion collisions, dealing with the challenge of expected Pb-Pb interaction rates of up to 50 kHz. For this purpose, a new silicon tracker is needed with greatly improved features in terms of determination of the distance of...
Jiayin Sun
(Stony Brook University)
16/08/2012, 16:00
Dielectron spectra in Au+Au collisions carry important information on the properties of the hot dense matter created in the early stage of the collisions. The earlier PHENIX measurement, using data taken in 2004 shows significant deviations from hadronic decay expectations. The most recent data set from 2010, taken with the the Hadron Blind Detector (HBD) upgrade designed to reduce the...
Mr
Raktim Abir
(Saha Institute of Nuclear Physics)
16/08/2012, 16:00
Most of the the calculations on gluon emission off a heavy quark, within perturbative QCD, have been performed in the literature using light cone gauge with eikonal approximations. Recently we revisited the issue in Feynman gauge that resulted in a very compact and elegant expression for the suppression factor for gluon emission off a heavy quark [1]. This generalization is valid for the full...
Dhevan Raja Gangadharan
(Ohio State University (US))
16/08/2012, 16:00
Quantum coherence is fundamental in the interpretation of geometrical information from HBT measurements. The effect of quantum coherence is not only to lower the correlation strength of HBT correlations but also to modify the shape. We present measurements of the source chaoticity from Pb+Pb sqrt(s) = 2.76 TeV collisions at the LHC using the ALICE detector. Three-pion and two-pion correlations...
Björn Bäuchle
(FIAS Frankfurt)
16/08/2012, 16:00
Photons, as all electromagnetic probes, can give direct access to the hot and dense phase of a heavy-ion reaction. We show calculations of direct photon emission at highest energies available with the UrQMD-hybrid model. UrQMD is a full microscopic+macroscopic transport/fluiddynamics hybrid model with hadron- and string-driven equilibration phase, a fll (3+1)-dimensional fluiddynamic hot and...
Prof.
Sanjay Ghosh
(Bose Institute)
16/08/2012, 16:00
Collective flow is an essential component in describing the
dynamics of relativistic heavy ion collisions. The flow characteristics are intimately related to the equation of state of the thermally equilibrated matter created in these collisions through the speed of sound. Using either the Bjorken or Landau hydrodynamics or a combination thereof it is possible to relate the
particle yields to...
Anne Sickles
(Brookhaven)
16/08/2012, 16:00
Reconstructed jets in heavy ion collisions are a crucial tool for
understanding the quark-gluon plasma. The separation of jets from
the underlying event is necessary, particularly in central heavy
ion collisions, in order to quantify medium modifications of the parton
shower. Here, we describe a method for quantifying the underlying event contributions in Au+Au collisions at...
Prof.
Jamie Nagle
(University of Colorado)
16/08/2012, 16:00
The PHENIX Experiment is proposing an exciting suite of upgrades called sPHENIX, with a first stage including a world class jet
detector with full electromagnetic and hadronic calorimetry capable of sampling up to 50 billion Au+Au collisions annually and measuring jets over a broad kinematic range and with high statistics (over 10 million jets above 20 GeV and over 100,000 jets above 40 GeV)....
Sener Ozonder
(University of Minnesota)
16/08/2012, 16:00
We consider a modified version of the McLerran-Venugopalan model where the thickness of the nucleus is finite and infrared divergences are removed by the color neutrality condition. The strong coupling constant and the nucleon size are treated as parameters. To determine these parameters, the x-dependent gluon distribution function is calculated at very low momentum, which is the region of...
Bhanu Sharma
(Panjab University)
16/08/2012, 16:00
The STAR experiment at Relativistic Heavy Ion Collider (RHIC) investigates the behaviour of strongly interacting matter at high density and searches for the possible formation of Quark Gluon Plasma (QGP). Event-by-event net charge fluctuation has been proposed as one of the indicators of QGP formation in heavy ion collisions. The fluctuation in net charge depends on the squares of the charges...
Ms
Neha Shah
(University of California Los Angeles)
16/08/2012, 16:00
The production of large number of multi-strange hyperons per central nucleus-nucleus collision at RHIC allows us to study hyperon-hyperon interactions through measurement of particle correlations and search for exotic particles like dihyperons. In 1977 Jaffe[1] predicted a six quark state, $H_{0}$-dibaryon, with hypercharge (Y) = 0 and Strangeness (S) = -2 to be stable against strong decay,...
Sanshiro for the PHENIX experiments Mizuno
(University of Tsukuba, RIKEN (JP))
16/08/2012, 16:00
Azimuthal anisotropy and particle species dependence of transverse momentum distribution have been studied actively because they reveal information about the QGP generated in high energy heavy ion collisions.
From the study of elliptic event anisotropy v_{2}, we have understood that azimuthal anisotropy is generated by initial participant geometry, with a role for the QGP property $\eta$/s...
Dr
Kun Liu
(Los Alamos National Laboratory)
16/08/2012, 16:00
E906/SeaQuest is a fixed-target experiment operated at Fermi National Accelerator Laboratory. Using the 120 GeV proton beams from the Main Injector, E906/SeaQuest measures the Drell-Yan production in the dimuon mass region of 4-8 GeV in p+p and p+A collisions over a wide xF range. Parton energy loss in QGP is considered as the dominant mechanism of the observed jet-quenching phenomena at RHIC...
Tinku Sarkar - Sinha
(Saha Institute of Nuclear Physics (IN))
16/08/2012, 16:00
The high energy density reached in pp collisions at LHC could be comparable with the energy density for heavy–ion collisions at lower energies (i.e. Au-Au collisions at RHIC) and it might lead to the observation of collective phenomena. The multiplicity of the collision can be used as the “centrality” variable in pp collisions at LHC.
In particular, the LHC provided p-p collisions at √s =...
Min Jung Kweon
(Ruprecht-Karls-Universitaet Heidelberg (DE))
16/08/2012, 16:00
Heavy quarks are expected to be a probe providing new constraints on partonic energy loss mechanisms in the medium produced in heavy-ion collisions at the LHC. In particular, the medium-induced parton energy loss is expected to depend on its mass and colour charge. The measurement of heavy quark production in pp collisions provides an important test of pQCD calculations and serves as a...
Tomas Aronsson
(Yale University (US))
16/08/2012, 16:00
High-energy heavy-ion collisions at the LHC allow for the study of the properties of the quark-gluon plasma (QGP). Heavy quarks, charm and bottom, produced in the initial hard scattering processes of the collision are excellent probes of the QGP.
When heavy quarks traverse the QGP they are expected to lose energy and such energy loss is predicted to be smaller than for gluons and light...
Dr
Umme Jamil Begum
(Debraj Roy College, Golaghat, Assam, India)
16/08/2012, 16:00
Charm quarks/antiquarks produced in the initial stage of heavy ion collisions, would traverse the quark gluon plasma, colliding with quarks and gluons and radiating gluons before appearing as D-mesons. Thus the final spectra of D-mesons would contain information of the medium modification suffered by the charm quarks/antiquarks. We have made a detailed study for the nuclear modification factor...
Sooraj Krishnan Radhakrishnan
(State University of New York (US))
16/08/2012, 16:00
The anisotropy associated with the initial dipole asymmetry in heavy ion collisions is studied via the first harmonic coefficient $v_{1,1}$ of the two-particle azimuthal angle correlations, within AMPT and HIJING model (AMPT is essentially HIJING + parton/hadron transport). For a broad selection of centrality, transverse momenta and pseudorapidity ($\eta$), a fitting method is used to...
Mr
Dustin Hemphill
(Purdue University)
16/08/2012, 16:00
We employ a grid based stochastic technique to solve the on-shell
Boltzmann transport equation including inelastic 3<->2 processes. The case of an interacting massless partonic gas in a longitudinally expanding Bjorken geometry is considered. The numerical accuracy of the algorithm is first rigorously established from comparisons to both static box calculations and earlier results from the...
Dr
Hanzhong Zhang
(Institute of Particle Physics, Central China Normal University)
16/08/2012, 16:00
The effect of initial fluctuations on partonic jet energy loss in a hydrodynamical background in high-energy heavy-ion collisions is studied within a next-to-leading order (NLO) perturbative QCD
parton model. An energetic parton jet is found to lose more energy loss with fluctuating initial conditions than that with smooth initial conditions due to initial dominative positive correlation...
Jinfeng Liao
(Indiana University & RIKEN BNL Research Center)
16/08/2012, 16:00
One of the main discoveries at RHIC is the strongly coupled quark-gluon plasma (sQGP), based particularly on the observed "perfect fluid" and strong jet quenching. One of the most interesting physics to see at LHC is whether and how such sQGP properties will change. Based on the deep and generic electric-magnetic duality, we've suggested that the QCD plasma contains the quarks and gluons...
Mr
Hiroshi Nakagomi
(Univ. of Tsukuba)