John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Why this Talk?
My disclaimer – My charge from the ALICE “Brass”:
“Summary of differences compared to RHIC,
what we have not done to compare to RHIC results,
where should we focus effort to gain knowledge?”
My view today – what we have done, still need to do….
on the “standard menu” of measurements
for better precision
determination of properties of the QGP!
People in ALICE are working on all of this….tremendous progress!
Emphasis on gaining physics knowledge from ALICE!
Apologies to those whose work I have not noted here…..
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
What Have We Learned? – Spacetime Evolution
“LHC & RHIC provide consistent picture” of dynamics & evolution of collisions
multiplicities, system size & lifetimes from RHIC to LHC
properties of medium (e, h/s, vs, ….?)
ALICE, Phys. Rev. Lett. 105, 252301 (2010)
Muller, Schukraft & Wylsouch, arXiv:1202.3233
Small differences due to initial conditions (PDF shadowing vs geometry, hard
processes ~ # binary collisions at LHC vs RHIC)?
John Harris (Yale)
Must establish initialAIM
conditions
– p-Pb
andWeek,
Pb-pApril
this19,
year!
Session, ALICE
Physics
More on Spacetime Evolution – Constraints
“LHC & RHIC provide consistent picture” of dynamics & evolution of collisions
multiplicities, system size & lifetimes from RHIC to LHC
properties of medium (e, h/s, vs, ….?)
ALICE, Phys.Lett. B696 (2011) 328
VLHC ~ 2 x VRHIC !
tf (LHC) ~ 1.4 x tf (RHIC) !
Size
John Harris (Yale)
Volume ~ dN/dh
tf ~ dNch/dh 1/3
tf (central PbPb) ~ 10 – 11 fm/c
Lifetime hydrodynamic expansion
AIM Session, ALICE Physics Week, April 19,
More on Spacetime Evolution
Slope changes at LHC vs RHIC
RHIC
Smooth extrapolation?
Somewhat stronger radial flow,
b ≈ 0.66, at LHC
John Harris (Yale)
LHC
Blast Wave
Fits
AIM Session, ALICE Physics Week, April 19,
More on Spacetime Evolution
Slope changes at LHC vs RHIC
RHIC
Smooth extrapolation?
Somewhat stronger radial flow,
b ≈ 0.66, at LHC
x3
John Harris (Yale)
LHC
Blast Wave
Fits
Enhanced baryon/meson ratio
at LHC like RHIC
Increases with centrality
Central B/m peak ratio 3x pp
PID Spectra – more particles
& higher
statistics
to April
higher
AIM Session,
ALICE Physics
Week,
19, pT
More on Spacetime Evolution
Enhanced baryon/meson ratio
at LHC like RHIC
Increases with centrality
Central B/m peak ratio 3x pp
x3
John Harris (Yale)
Enhanced baryon/meson ratio
at LHC like RHIC
Increases with centrality
P. Kalinak APW
Peak central B/m ratio 3x pp value
PID Spectra – more particles
& higher
statistics
to April
higher
AIM Session,
ALICE Physics
Week,
19, pT
More on Spacetime
Evolution
RHIC
Enhanced baryon/meson ratio
at LHC like RHIC
Increases with centrality
Central B/m peak ratio 3x pp
x3
John Harris (Yale)
LHC
P. Christiansen APW
Blast Wave
Fits
Enhanced baryon/meson ratio
at LHC like RHIC
Increases with centrality
P. Kalinak APW
Peak central B/m ratio 3x pp value
PID Spectra – more particles
& higher
statistics
to April
higher
AIM Session,
ALICE Physics
Week,
19, pT
Mounting Evidence from Thermal Fits!
Particles yields at RHIC
 equilibrium abundances
 universal hadronization Tcritical
Same at LHC, but more work needed:
(also to understand proton yields)
Need to complete the ratio studies!
extrapolations, feed-down, …
protons?
Calculation - A. Andronic et al., Phys. Lett. B 673:142,2009
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Elliptic Flow vs Collision Energy
ALICE, Phys. Rev. Lett .105, 252302 (2010)
v2 {4}
STAR: PRC 77 (2008) 054901; PRC 75 (2007) 054906
STAR
preliminary
v2 {EP}
v2 vs transverse momentum (pT)
same for 2.76 TeV down to 39 GeV!
pT (GeV/c)
Change in v2 vs pT
below 39 GeV (at 7.7 & 11.5 GeV)!
pT (GeV/c)
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Elliptic Flow – Identified Particles
ALICE, M. Krzewicki, R. Snellings, QM 2011
ALICE (p, K, p) data points
PHENIX bands: Phys. Rev. Lett. 91, 182301 (2003)
STAR bands: Phys. Rev C 77, 054901 (2008)
Hydro curves: Shen, Heinz, Huovinen & Song, arXiv:1105.3226
Larger mass splitting at LHC than at RHIC
Hydro: CGC initial conditions, h/s = 0.2
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Identified Particle Elliptic Flow
Hydro: Shen, Heinz, Huovinen, Song, Phys. Rev. C84 (2011) 044903.
Clear mass ordering!
John Harris (Yale)
nq scaling?
Dynamics more complicated!
AIM Session, ALICE Physics Week, April 19,
J/y Elliptic Flow!
J/y
m+m- in ALICE Muon Arm
finite v2 observed
Most central bin
dominated by fluctuations
H. Yang APW
H. Yang APW
For different bkgds.
J/y
m+m- in ALICE Muon Arm
20 – 60 % centrality
v2 (pT) dependence
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
J/y Elliptic Flow!
e+e- in STAR
J/y
20 – 60 % centrality
no v2 signal!
J/y
m+m- in ALICE Muon Arm
J/y
m+m- in ALICE Muon Arm
finite v2 observed
Most central bin
dominated by fluctuations
H. Yang APW
For different bkgds.
20 – 60 % centrality
v2 observed 1.5 < pT < 4
GeV/c
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Direct g Elliptic Flow..
v2inc = v2 of inclusive g
from conversions
V2decays = v2 of decay g’s
Next step: extract
v2dir = v2inc +
g-dirv
2
v2inc  v2decays
Rg 
(R= Ninc/N1decays)
D.
Lohner,
John
Harrisreported
(Yale) by C. Loizides APW
AIM Session, ALICE Physics Week, April 19,
Direct g Elliptic Flow from PHENIX
Au+Au at 200 GeV PHENIX, arXiv:1105.4126
g-dirv using
2
technique outlined on previous slide
Large g-dirv2 at lower pT ~ v2p0
Too large for theory!
John Harris (Yale)
g-dirv
2
at higher pT ~ hard
scattering?
AIM Session, ALICE Physics Week, April 19,
Theorists Working on Shear Viscosities
Hydro: Qui, Shen, Heinz, Phys. Lett. B707 (2012) 151.
Zeroing in on h/s and initial conditions?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Shear Viscosity from v2 & v3
Hydro: Schenke, Jeon, Gale, Phys. Lett. B702 (2011) 59.
Sensitivities of h/s and initial conditions to vn
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Elliptic Flow at Large pT
High pT v2 from jets?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Elliptic Flow at Large pT
CMS and ATLAS high pT results
CMS, arXiv:submit/0450742
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Should ask ourselves
“What Will it Take to Be Able to Say…?”
“We understand the shear viscosity, sound
velocity, EOS, other properties of the Medium!”
e.g. – constituents?
c-symmetry?
deconfinement?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
e+e- in PHENIX….. Properties of the Medium
Low mass di-leptons
The original case for
medium effects!
Min. Bias Au+Au
PHENIX, PRC81,
034911(2010),
arXiv:0912.0244
Space-time evolution?
Shuryak, arXiv:1203.1012v1
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Au + Au
Still work to be done!
John Harris (Yale)
e+e- in STAR
Inconsistent with PHENIX?
AIM Session, ALICE Physics Week, April 19,
Au + Au
e+e- vs Centrality in PHENIX
Low mass di-lepton
Enhancement!
Increases with centrality.
Centrality dependence:
PHENIX, PRC81,
034911(2010),
arXiv:0912.0244
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Central Au + Au
e+e- in STAR
Difficult…consistency…!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Vector Meson Studies in ALICE pp
ALICE, Phys. Lett. B710 (2012) 557.
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Towards Properties of the Medium (ALICE)
ALICE Central Collision e+e- data, C. Baumann APW
Cocktail not quite complete…. “enhancement apparent”
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Towards Properties of the Medium (ALICE)
ALICE 20 – 80 % centrality e+e- data, C. Baumann APW
Clearly a difficult task! Much can be done prior to upgrades!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Suppression of High pT Particles
RAA
p /g
N AA
=
N coll N ppp/ g
CMS, arXiv:1202.2554v1
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Suppression of High pT Particles
RAA
p /g
N AA
=
N coll N ppp/ g
RAA at LHC theory:
pQCD behavior!
Inconsistent with
CGC
initial conditions.
B. Betz and M. Gyulassy, arXiv:1201.0281
John Harris (Yale)
Requires running
coupling constant!
Isn’t this now AIM
purely
pQCD
with running
Session,
ALICE Physics
Week, Aprila?
19,
Suppression of “Intermediate pT” Particles
RAA
p /g
N AA
=
N coll N ppp/ g
RAA at LHC theory:
pQCD behavior!
A few more details left.
B. Betz and M. Gyulassy,
arXiv:1201.0281
John Harris (Yale)
Begs for RAA for allAIM
i.d.’ed
particles
to confront
theory!
Session,
ALICE –
Physics
Week, April
19,
Suppression of “Intermediate pT” Pions
ALICE, P. Christiansen APW
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Suppression of “Intermediate pT” Kaons
ALICE, P. Christiansen APW
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Suppression of “Intermediate pT” Protons
ALICE, P. Christiansen APW
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Suppression of “Intermediate pT” p0
Work of Dmitri Peresunko, reported by C. Loizides APW
John Harris (Yale)
Consistent
charged
Progress!
AIMwith
Session,
ALICE pions.
Physics Week,
April 19,
More to do on Photons!
Tinit ~ 370 MeV
PHENIX, PRL 96 (2006) 202301
RAAdir-g vs pT
PHENIX, PRL 104 (2010) 132301
“Enhanced production of Direct g ...
Implications for Initial Temperature”!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Parton Energy Loss in the Medium
Heavy Flavor production, flow and propagation (RAA)
To understand:
quark, gluon & flavor
dependence.
Muller, Schukraft & Wylsouch, arXiv:1202.3233
John Harris (Yale)
Looks like ~pQCD at
pT > 10ALICE
GeV/c…except
need…
AIM Session,
Physics Week, April 19,
Heavy Quark Energy Loss in the Medium
WHDG prediction for B
M. Gyulassy, BNL Seminar 2012
Will B-quarks Behave as pQCD predicts?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Heavy Quark Energy Loss in the Medium
ALICE, arXiv:1203.2160
“Suppression of high pT D mesons in central Pb-Pb at √sNN = 2.76 TeV”
pQCD with parton E-loss describes both charm & light hadrons!
…….with little nuclear shadowing!
Extend
pT range
! 19,
John Harris (Yale)
AIM Session, ALICE
Physics
Week, April
Aside – J/y in pp at 7 TeV!
Mid-rapidity J/y more likely produced in high multiplicity pp events!
Theory in a quandary!?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
J/Y Suppression at SPS & RHIC
J/ψ suppressed at RHIC ~
SPS!
Increases with centrality
(not shown here).
J/ψ – more suppressed forward.
Partly due to cold nuclear matter!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
J/Y Suppression at RHIC & LHC
CMS, PRL 107 (2011) 052302
J/ψ less suppressed than at RHIC
John Harris (Yale)
High pT J/ψ near ycm more suppressed than
at RHIC
→ energy loss of charm quark
AIM Session, ALICE Physics Week, April 19,
Recent Word by PHENIX – J/Y Suppression at RHIC
PHENIX, arXiv:1103.6269v1
Suppression of J/y at forward rapidity
stronger than at midrapidity.
Have compared to recent calculations that
include
gluon saturation
gluon shadowing
initial-state parton energy loss
cold nuclear matter breakup
color screening
charm recombination.
J/y suppressed beyond cold-nuclearmatter effects.
Disagreement between models and d+Au
data precludes using these models to
quantify hot nuclear matter suppression.
ALICE – Emphasizes importance of p-Pb and Pb-p this year!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
U Suppression at RHIC & LHC
CMS, PRL 107 (2011) 052302
U(2s), U(3s) suppressed wr to U(1s),
& relative to p+p collisions
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
U Suppression at RHIC & LHC
CMS, PRL 107 (2011) 052302
ALICE in progress!
Mmm (GeV/c2)
ALICE, J. Castillo, reported by D. Das APW
U(2s), U(3s) suppressed wr to U(1s),
& relative to p+p collisions
ALICE – Progress! Should also be able to analyze Y in e+e- channel in EMCal!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Jets at the LHC – Di-Jet Energy Imbalance!
Trigger
jet
Energy Asymmetry: AJ = ET1 – ET2 /
ET1 + ET2
for Df > p/2
Azimuthal Angular
Correlations
Away-side jet
John Harris (Yale)
ET1 > 100 GeV
ET2 > 25 GeV
AIM Session, ALICE Physics Week, April 19,
Where does the Energy Go? – CMS
PRC 84 (2011) 024906
dev
Energy/momentum balance in event is carried by
low momentum particles at large angles to jets!
pQCD, vacuum fragmentation, thermalization of lost energy?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
A Lot to Do & Still to Come from Jets in ALICE
Jets – (relative to reaction plane for geometry / pathlength selection)
(relative to pp)
spectra (understand soft background in Pb-Pb)
changes in intra-jet structure
correlations & energy balance
jet-hadron
hadron-jet
g-jet
di-jet
B-jets (for quark propagation in medium)
vn of jet (impact on flow analyses)
Use some of above for event selection criteria
e.g. di-jet energy imbalance
Must understand parton propagation energy loss processes in the medium!
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
More on Spacetime Evolution
Scope of the Light Flavour Spectra PWG
Global Event Observables (GEO):
•
•
•
•
Multiplicity (dNch/dη) distributions in Pb-Pb collisions;
Measurements in the forward region (VZERO, FMD, PMD);
Transverse energy;
...Transverse radial flow studies (also in Spectra).
Chiara Oppedisano and Jens Jørgen Gaardhøje
Spectra (π,K,p via dE/dx, TOF, Čerenkov):
•
•
•
•
•
Light flavour hadron yields and pT spectra;
Statistical thermal description;
High-pT spectra (non-identified, relativistic rise) and RAA;
(Anti-)nuclei measurements;
...Multiplicity dependence.
Peter Christiansen and Roberto Preghenella
Strangeness (topological analyses):
•
•
•
•
Strange hadron (Λ, K0s) analyses: pT spectra and RAA;
Multi-strange baryons (charged Ξ and Ω) ;
Hyper-nuclei measurements;
...V0 correlations (intermediate to high pT: leading track and jets).
Lee Barnby and Domenico Elia
Resonances (invariant mass analyses):
•
•
•
•
Meson resonances (K*,ϕ) analyses: pT spectra and yields;
Baryon resonances (Σ*, Λ*, Ξ*) ;
Resonance properties and production in jets;
...Exotica (H-dibaryon...).
M.Floris & B.Hippolyte for PWG-LF
Angela Badalà and Christina Markert
APW’12 - Frascati
2/3
Tremendous effort on many different analyses!
Need to consider physics message papers across analyses
(e.g. v2,3,…, RAA for ID’ed particles)
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,
Big Questions – QGP at RHIC & LHC
-
How does the system evolve and thermalize from its initial state?
What is the initial state (CGC?)?
-
What are the properties & constituents (vs. T) of the QGP?
-
Can we understand parton propagation & energy loss at fundamental level?
What can we learn about the medium response?
-
How does hadronization take place?
-
Can we understand & extract all contributions to quarkonium suppression?
What does it tell us?
-
Is the QCD Phase Diagram featureless above Tc? Coupling strength vs T….
-
Are there new phenomena? Whatever happened to c-symmetry?....
-
Can there be new developments in theory (lattice, hydro, parton E-loss,
string theory…) and understanding……across fields……?
John Harris (Yale)
AIM Session, ALICE Physics Week, April 19,