M' J' Tannenbaum 196

1
Results from RHIC with Implications
for LHC
M. J. Tannenbaum Brookhaven National
Laboratory Upton, NY 11973 USA
International School of Subnuclear Physics The
Most Unexpected at LHC and the Status of High
Energy Frontier 47th
Course-Erice, Sicily, Italy
Aug. 29- Sept. 7, 2009
2
High Energy Nucleus-Collisions provide the means
of creating Nuclear Matter in conditions of
Extreme Temperature and Density

• At large energy or baryon density, a phase
  transition is expected from a state of nucleons
  containing confined quarks and gluons to a state
  of deconfined (from their individual nucleons)
  quarks and gluons covering a volume that is many
  units of the confinement length scale.

3
One Big Grape
Rep. Prog. Phys. 63 (2000) 1511
??? (1 - e-?r)/?r
4
The Quark Gluon Plasma (QGP)

• The QCD confinement scale---when the string
  breaks---is order

1/?QCD 1/m?1.4 fm

• The QCD potential becomes screened with
  increasing temperature, T, in analogy to
  increasing Q2 ?s(T) becomes smaller, reducing
  the binding energy, and the string tension ?(T)
  becomes smaller, increasing the confinement
  radius.

• For r lt 1/? a quark does feel the full color
  charge but for r gt1/? the quark is free
  of the potential, effectively deconfined

5
The Quark Gluon Plasma (QGP)

• The state should be in chemical (particle type)
  and thermal equilibrium ltpTgt T

• The major problem is to relate the thermodynamic
  properties, Temperature, energy density, entropy
  of the QGP or hot nuclear matter to properties
  that can be measured in the lab.

6
The gold-plated signature for the QGPJ/?
Suppression

• In 1986, T. Matsui H. Satz PL B178, 416 (1987)
  said that due to the Debye screening of the color
  potential in a QGP, charmonium production would
  be suppressed since the cc-bar couldnt bind.

• This is CERNs Heavy Ions claim to fame but
  the situation is complicated because J/? are
  suppressed in pA collisions. NA50
  collaboration, M.C. Abreu, et al., PLB 477, 28
  (2000)

7
How to discover the QGP-1990-91

• The Classical road to success in RHI Physics
  J/? Suppression

So we designed a detector to do this

• Major background for e? detection is photons and
  conversions from ?0. but more importantly
• Need an electron trigger for full J/? detection ?
  EMCal plus electron ID at trigger level.
• High pT ?0 and direct ? production and
  two-particle correlations are the way to measure
  hard-scattering in RHI collisions where jets can
  not be detected directly---gt segmentation of
  EMCal must be sufficient to distinguish ?0 and
  direct ? up to 25 GeV/c (also vital for spin)
• Charm measurement via single e? (Discovered by
  CCRS experiment at CERN ISR)
• So we designed PHENIX to make these measurements

8
Mike, is there a real collider detector at
RHIC?---J. Steinberger

• PHENIX is picturesque because it is not your
  fathers solenoid collider detector
• Special purpose detector designed and built to
  measure rare processes involving leptons and
  photons at the highest luminosities.
• possibility of zero magnetic field on axis
• minimum of material in aperture 0.4 Xo
• EMCAL RICH e? i.d. and lvl-1 trigger

• ? ?0 separation up to pT 25 GeV/c
• EMCAL and precision TOF for h? pid

9
Detecting electrons means detecting all
particlesPHENIX
10
p0's in pp ?s200 GeV Data vs. pQCD

• Result from run2 published-a classic
• PRL91 (2003) 241803
• New result from run5
• preliminary
• Comparison of ?0 cross section
• Next-to-leading order(NLO) pQCD
• CTEQ6M KKP or Kretzer
• Matrix calculation by Aversa, et. al.
• Renormalization and factorization scales are set
  to be equal and set to
• 1/2pT, pT, 2pT
• Calculated by W.Vogelsang

NLO-pQCD described very well down even to pT 1
GeV/c
Inclusive invariant ?0 spectrum is pure power law
for pT3 GeV/c n8.10.1
11
Three things are dramatically different in
Relativistic Heavy Ion Physics
than in p-p physics

• the multiplicity is A200 times larger in AA
  central collisions than in p-p ?huge energy in
  jet cone 300 GeV for R1 at ?sNN200 GeV

• huge azimuthal anisotropies which dont exist in
  p-p which are interesting in themselves, and are
  useful, but sometimes troublesome.

• space-time issues both in momentum space and
  coordinate space are important in RHI for
  instance what is the spatial extent of parton
  fragmentation, is there a formation
  time/distance?

12
Soft Physics Dominates Particle production
in both p-p and AA (Relativistic Heavy Ion)
collisions
13
AuAu Central Collisions cf. p-p
STAR-Jet event in pp
STAR AuAu central
PHENIX AuAu central
per unit velocity to beam
14
Extreme-Independent or Wounded Nucleon Models for
soft particle Multiplicity or ET

• Number of Spectators (i.e. non-participants) Ns
  can be measured directly in Zero Degree
  Calorimeters (more complicated in Colliders)
• Enables unambiguous measurement of (projectile)
  participants Ap -Ns
• For symmetric AA collision Npart2 Nprojpart
• Uncertainty principle and time dilation prevent
  cascading of produced particles in relativistic
  collisions ? h/mpc gt 10fm even at AGS energies
  particle production takes place outside the
  Nucleus in a pA reaction.
• Thus, Extreme-Independent models separate the
  nuclear geometry from the dynamics of particle
  production. The Nuclear Geometry is represented
  as the relative probability per BA interaction
  wn for a given number of total participants
  (WNM), projectile participants (WPNM), wounded
  projectile quarks (AQM), or other fundamental
  element of particle production.
• The dynamics of the elementary underlying
  process is taken from the data e.g. the measured
  ET distribution for a p-p collision represents, 2
  participants, 1 n-n collision, 1 wounded
  projectile nucleon, a predictable convolution of
  quark-nucleon collisions.

15
Summary of Wounded Nucleon Models

• The classical Wounded Nucleon (Npart) Model
  (WNM) of Bialas, Bleszynski and Czyz (NPB 111,
  461 (1976) ) works only at CERN fixed target
  energies, ?sNN20 GeV.
• WNM overpredicts at AGS energies ?sNN 5 GeV
  (WPNM works at mid-rapidity)
• WNM underpredicts for ?sNN 31 GeV

16
The Kink-M.Gazdzicki-JPG30(2004)S701
pions/participant
AA
pp
Wounded nucleon model only works at ?s20 GeV,
where it was discovered by Busza, Bialas and
fails above and below ?s20 GeV wounded
projectile nucleons below ?s20 GeV at
mid-rapidity wounded projectile quarks (AQM) at
larger ?s
17
Anisotropic (Elliptic) Transverse Flow--an
Interesting complication in AA collisions

• spatial anisotropy? momentum anisotropy

• Perform a Fourier decomposition of the momentum
  space particle distributions in the x-y plane
• v2 is the 2nd harmonic Fourier coefficient

Directed flow zero at midrapidity
Elliptical flow dominant at midrapidity
18
Elliptic Flow v2 in AuAu Central 200 GeV
Universal in constituent quark Kinetic Energy
STAR-PRC72 (2005) 014904
PHENIX PRL98 (2007) 162301
?large v2 for high and low pT, plateaus for pTgt2
GeV/c for mesons, scales in KE/constituent quark

??-meson (not shown) follows same scaling
further implies flow is partonic not hadronic
?KE
scaling suggests Hydrodynamic origin.
? v2 for pTgt 1 GeV/c suggests low
viscosity, D.Teaney, PRC68 (2003) 034913, the
perfect fluid?? ? Quantum
Viscosity Bound from string theory reinforces
this idea, Kotvun, Son, Starinets, PRL 94 (2005)
111601
19
2 soft physics questions for the LHC

• Will soft processes at LHC scale like AQM or be
  higher, proportional to the number of
  binary-collisions Ncoll rather than the number of
  constituent-quark-participants?
• Will the QGP at the LHC be a superfluid like the
  liquid He coolant in the magnets?

20
Will soft Nch or ET at LHC show Ncoll scaling?
AA
pp
This is day-1 measurement in AA if pp available
Wit Busza-- HIC at LHC Last Call for predictions
2007
AuAu/pp (LHC)1.4-1.7 cf 1.6 at RHIC (same)?AQM
but if it goes to 5.7 then Ncoll scaling for soft
processes---Unlikely!
21
v2 at LHC
x 1.6
Compilation of data from NA49, Phys. Rev. C68
(2003) 034903
Wit Busza-- HIC at LHC Last Call for predictions
2007
22
v2--is there a Hydro Limit?
Good bet for interesting early result
Alt,et al, NA49 Phys. Rev. C68 (2003) 034903
23
Latest viscous hydro v2 predictions, ?/s etc
?/s is the ratio of the shear viscosity to the
entropy density
It seems that viscous hydro is more sensitive to
?/s than to the peak energy density e0. If Busza
is correct does this mean negative ?/s (!) at
LHC--a superfluid QGP to go along with the
superfluid He magnet cooling?
H. Song and U. Heinz Phys. Rev. C78 (2008) 024902
Also see Niemi, Eskola, Ruuskanen arXiv0806.1116
24
Now, Back To Hard-Scattering at RHIC
25
p-p collisions at RHIC ?0 production (PHENIX)
?s200 GeV
No surprise (to me) that NLO pQCD agrees with data
PRD76(2007)051006(R)
26
BBK 1971
S.M.Berman, J.D.Bjorken and J.B.Kogut, Phys. Rev.
D4, 3388 (1971)

• BBK calculated for pp collisions, the inclusive
  reaction
• AB ?C X when
  particle C has pTgtgt 1 GeV/c
• The charged partons of DIS must scatter
  electromagnetically which may be viewed as a
  lower bound on the real cross section at large
  pT.

27
CCR at the CERN-ISRDiscovery of high pT ?0
production in p-p
F.W. Büsser, et al., CERN, Columbia,
Rockefeller Collaboration Phys. Lett. 46B, 471
(1973)
Bjorken scaling PR179(1969)1547 ? BermanBjKogut
scaling PRD4(71)3388 ? Blankenbecler, Brodsky,
Gunion xT2pT/?s Scaling PL 42B, 461 (1972)
neff gives the form of the force-law between
constituents neff4 for QED

• e-6pT breaks to a power law at high pT with
  characteristic ?s dependence
• Large rate indicates that partons interact
  strongly (gtgt EM) with other.
• Data follow xT2pT/?s scaling but with neff8!,
  not neff4 as expected for QED

28
First prediction using QCD 1975
29
Leon Lederman on high pT-1975
30
CCOR 1978--Discovery of REALLY high pTgt7 GeV/c
at ISR
CCOR A.L.S. Angelis, et al, Phys.Lett. 79B, 505
(1978)
8
QCD Cahalan, Geer, Kogut, Susskind, PRD11, 1199
(1975)
5
neff5 (4) as predicted for QCD
31
ISR Expts more interested in n(xT,?s) than
absolute cross section
Athens BNL CERN Syracuse Collaboration,
C.Kourkoumelis, et al Phys.Lett. 84B, 279 (1979)
But n(xT,?s) agrees
cross sections vary by factor of 2
32
CCRS-1974 Discovery of direct e?10-4?? at ISR
not due to internal conversion of direct photons
CCRS PLB53(1974)212 NPB113(1976)189
Data points (ee-)/2 lines 10-4 (??-)/2
?Farrar and Frautschi PRL36(1976)1017 proposed
that direct leptons are due to internal
conversion of direct photons with ?/?10-20 to
ee- (d?/dm1/m) for pTgt1.3 GeV/c. CCRS looks,
finds very few events, sets limits excluding
this.
p.s. these direct e? are due to semi-leptonic
decay of charm particles not discovered until
1976, 2 year later Hinchliffe and
Llewellyn-Smith NPB114(1976)45
33
CCRS e/? Lepton/Photon SLAC 1975
34
Bourquin-Gaillard (1976)-the first cocktail
note conjectured charm meson whose discovery
was published in August1976 PRL37(1976)255 but
received 14 June 1975!!!!
What about those low pT points that dont fit.
Does that remind you of something?
35
One of the STARs of 1976-CHORMN-30o
Lots of experiments not designed for the purpose
wanted to get into the act. This is only one
example, see Bourquin-Gaillard for more
36
A Typical Paper on charm c.1990
A fairer comparison from PHENIX PRL88(2002) 192302
e.g R. Vogt, ZPC71(1996)475 No citations to the
experiments! Tavernier RPP50(1987)1439 doesnt
even cite CCRS since 1974 was before charm or J/?
were discovered.
Note that CCRS (1974) and Basile,
NuovoCimentoA65(1981)421 agree with each other
and theory
37
Fixed target finally got it right with Si VTX
From J.A.Appel ARNPS 42(1992)367
38
Zero field on axis avoids losing one e? from a
pair
From CCRS PLB53, 212 (1974) Discovery of direct
e? at the CERN-ISR (S.N.Whites thesis)
Zero field on beam axis is best for this
measurement can detect or reject conversion or
Dalitz pairs before they open and watch them open
in bending plane of magnet which is off the axis.
39
Converter run separates photonic from
non-photonic e?
From CCRS PLB53, 212 (1974) Discovery of direct
e? at the CERN-ISR (S.N.Whites thesis)

• Background is measured in the signal channel
  single e? and not calculated from measured pairs.
• Low mass ee- pairs are detected so can
  calculate their negligible contribution to the
  signal. Selected conversions extrapolate to 0 at
  the Dalitz point to check the method.

• Probability of internal external conversion
  per photon is

where ?2/2Dalitz (internal conversion) branching
ratio per photon0.6 ?0, 0.8 for ????.
Extrapolates to zero for a photonic source at the
Dalitz point essentially same for ?0 and( ?)
40
Basile(Zichichi) NC65A(1981)421
41
Basile(Zichichi) NC65A(1981)421
Note that CCRS (1974) and Basile,
NuovoCimentoA65(1981)421 agree with each other to
within 30
42
J/Psi and direct e?
Best
Not cause of direct e?
First J/? at ISR
CSZ NPB142(1978)29 ?pT?1.10?0.05 GeV/c
CCRS NPB113(1976)189 direct e? not due to J/?
CCRS PLB56(1975)482 2nd J/? in Europe
43
Sam Ting Nobel Lecture 11Dec 1976
44
Jim Cronin, another Nobel Laureate (but
incorrect on this issue)
Proc 1977 Int. Sym. Lepton-Photon Interactions,
Hamburg
45
Cronin conclusions, then discussion
MJT-people who try to measure single leptons
become the worlds experts on ? Dalitz decay, see
erratum M.R.Jane et al, PLB73(1978)503, a
correction of the branching ratio quoted in their
original eta-dalitz (form factor) measurement,
PLB59 (1975)103.
46
ISR direct photon production correlations
See the classic paper of Fritzsch and Minkowski,
PLB 69 (1977) 316-320
No evidence for bremss. contribution to direct
?--same side correlation is zero--see CMOR
NPB327, 541 (1989) for full list of references.
47
Di-Jet structure of events with high pT ?0
measured via 2-particle correlations
CCOR, A.L.S.Angelis, et al Phys.Lett. 97B, 163
(1980) Physica Scripta 19, 116 (1979)
pTt gt 7 GeV/c vs pT
48
ICHEP-Paris1982 first unbiased jet (UA2)
first measurement of QCD subprocess angular
distribution using ?0-?0 correlations (CCOR)
DATA CCOR NPB 209, 284 (1982)
p-p
QCD
49
Recap of discoveries and techniques from the CERN
ISR which are in use at RHIC (AuAu and pp).
G. Giacomelli and M. Jacob, Phys. Rept. 55 (1979)
1-132 M. Jacob and K. Johnsen, CERN Yellow Report
84-13

• The rapidity plateau. (Not discussed in this
  talk. )

• Hard scattering in p-p collisions via particle
  production at large pT which proved that the
  partons of DIS strongly interacted with each
  other. xT scaling measurements to find the
  underlying physics.

• Proof using same-side and away side two particle
  correlations that high pT particles in p-p
  collisions are produced from states with two
  roughly back-to-back jets which are the result of
  scattering of constituents of the nucleons as
  described by QCD, which was developed during the
  course of these measurements.

• direct lepton (e?) production from the decay of
  (unknown at that time-1974) particles composed of
  b and c quarks.

• direct photon production

• first and only J/Psi cross section measurement
  for all pair pT ? 0 at a hadron collider, until
  PHENIX at RHIC PRL 92 (2004) 051802 and CDF
  PRD 71(2005) 032001 (15 years after their first
  publication)

50
From ISR to RHIC Second Lecture
51
p-p collisions at RHIC ?0 production (PHENIX)
?s200 GeV
No surprise (to me) that NLO pQCD agrees with data
PRD76(2007)051006(R)
52
ISR ?0 vs RHIC p-p ? RHIC pp vs AuAu
53
High pT in AB collisions---TAB Scaling
view along beam axis

• For point-like processes, the cross section in
  pA or AB collisions compared to p-p is simply
  proportional to the relative number of pointlike
  encounters
• A for pA, AB for AB for the total rate
• TAB the overlap integral of the nuclear profile
  functions, as a function of impact parameter b

54
A Brief History of the EMC effect ?A DIS
note disagreement
A1.00
M.May, et al, PRL 35 (1975) 407. Plot is online
result shown by Gabathuler at Electron/Photon 1973
EMC, J.J.Aubert, et al, PLB 123(1983) 275-278
NMC, M.Arneodo, et al, NPB 481(1996) 23-39
55
M. May, et al.,
56
62.4 GeV-the importance of comparison data
Correct plot of R?0AA 62.4 vs 200 GeV
Black points use best guess/fit to ISR 62.4 GeV
data. Red points use our own new measurement
PRD79 (2009)012003
Similar R?0AA at 62.4 and 200 GeV (for pT gt 6
GeV/c) in Central AuAu
Problem is much worse at LHC as there is no
existing comparison data--Vital to measure pp at
same ?s (or above and below) as AA
57
Suppression of ?0 is arguably the major discovery
at RHIC. Energy loss in medium?
Au Au ?sNN200 GeV-QM 2005
?0 suppressed by a factor of 5 compared to
point-like scaling for 3lt pTlt 20 GeV/c!
Non-identified h? and ?0 are different for pTlt 6
GeV/c? particle ID is important.
Original ?0 discovery, PHENIX PRL 88
(2002)022301 latest preprint 0801.4020 nucl-ex
58
BUT-J/? Suppression (RAA) is the same at
mid-rapidity (PHENIX ee-) as at lower ?sNN!!!

• RAA vs. Npart integrated over pT
• NA50 at SPS
• 0ltylt1
• PHENIX at RHIC
• ylt0.35

AuAu
PHENIX PRL 98, 232301 (2007)
This was CERN-Heavy Ions main claim to fame in
the infamous press conference of 2000 claiming
observations consistent with the predicted
signatures of a QGP. Will have to wait for LHC
to find out whether J/? merely act like ordinary
hadrons low pT or whether they are actually
probes of deconfinement as predicted by Matsui
and Satz PLB178(1986)416. Also see discussion by
MJT in Rep.Prog.Phys. 69 (2006)2005
Bar uncorrelated error Bracket correlated
error Global error 12 is not shown
59
J/? Suppression--My Nightmare Scenario

• Many new Explanations.
• One exampleGrandchamp, Rapp, Brown PRL 92,
  212301 (2003)
• In-media dissolution
• Plus regeneration from off-diagonal c-cbar
  pairs

The Nightmare is that nobody will believe this.
Must see J/? enhancement to believe?Wait for LHC
result
60
New NA50 CERN fixed target pA baseline at same
?sNN as AA--Comparison with new RHIC results

• Both Pb-Pb and Au-Au seem to depart from
  the reference curve at NPart200
• For central collisions more important
  suppression in Au-Au with respect to Pb-Pb

Systematic errors on the CNM reference are shown
for all points
Roberta Arnaldi-ECT May2009
61
Quarkonia Deconfinement
Debye screening predicted to destroy J/?s in a
QGP with other states melting at different
temperatures due to different sizes or binding
energies.
Different lattice calculations do not agree on
whether the J/? is screened or not at RHIC and
some claim that suppression at CERN was not the
direct J/? but only the feeddown J/? from
suppressed ? and ?c
Satz, hep-ph/0512217, Karsch,Kharzeev,Satz PLB637
(2006)75
Mocsy, WWND08
inspired by Mike Leitch ECT-May09
5/25/2009
61
62
Quarkonia Production Suppression Upsilons in
pp

• Cross section follows world trend
• Baseline for AuAu

PHENIX-QM2009-
5/25/2009
62
63
Quarkonia Upsilons Suppressed in AuAu at RHIC
RAuAu 8.5,11.5 lt 0.64 at 90 C.L.
--- Includes ?1S2S3S ---
PHENIX-QM2009-
5/25/2009
63
64
Good Betting Opportunity at LHC
Will Peter Higgs or Helmut Satz have to wait
longer to find whether they are right?
65
Direct photon production-simple theory hard
experiment
See the classic paper of Fritzsch and Minkowski,
PLB 69 (1977) 316-320
yc
small-ignore
yd
Analytical formula for ?-jet cross section for a
photon at pT, yc (and parton (jet) at pT, yd)
fg(x) and F2(x) are g and q pdfs in nuclei A,B
66
Experimental problem is HUGE background from
?0???, ????, etc. But this is less of a problem
in AuAu due to suppression of ?0
PHENIX PRL94 (2005) 232301
x (1.19)0.335
?/?00.50
67
2004--Direct Photons in AuAu 200 GeV follow TAB
scaling from p-p for all centralities-no
suppression
1) Proves that initial state Au structure
function is simply a superposition of p-p
structure functions including g(x).
AuAu

2)Direct photons unaffected by QCD medium in
AuAu ? ?0 suppression is medium effect
PHENIX PRL94 (2005) 232301
68
Comparison with other p-p data and pQCD
P. Aurenche et al Phys. Rev. D 73, 094007 (2006)
PHENIX direct photon p-p data clarifies
longstanding data/theory puzzle
PHENIX PRL 98 (2007) 012002
69
QM2005-direct ? in AuAu via internal conversion
Kroll Wada PR98(1955) 1355
PHENIX NPA774(2006)403
Eliminating the ?0 background by going to
0.2ltmeelt0.3 GeV enables direct ? signal to be
measured for 1ltpT lt3 GeV/c in AuAu. It is
exponential, does that mean it is thermal. We
must see whether p-p direct ? turns over as pT ?0
as in Drell-Yan or exponential like for ?0
70
QM2008 direct ? in p-p via internal conversion
arXiv0804.4168v1
Lowest pT direct ? ever measured in p-p (and
AuAu). Curves are pQCD extrapolated (W.Vogelsang)
This is a major discovery, p-p result turns over
as pT?0, follows the same function B(1pT2/b)-n
used in Drell Yan Ito, et al, PRD23, 604 (1981)
. Fit to
AuAu is A e-pT/T ?TAA? Bpp(1pT2/bpp)-npp.
Significance of exponential (thermal?) is gt 3 ?
71
Suppression is a Final State Medium Effect

• Energy loss of partons in dense matter--A medium
  effect predicted in QCD---Energy loss by colored
  parton in medium composed of unscreened color
  charges with thermal mass ? by gluon
  bremsstrahlung--LPM radiation-of gluons
• Gyulassy, Wang, Vitev, Baier, Wiedemann
• See nucl-th/0302077 for a review.
• Baier, Dokshitzer, Mueller, Peigne, Shiff,
  NPB483, 291(1997), PLB345, 277(1995), Baier
  hep-ph/0209038,

• From Vitev nucl-th/0404052

?Bj ? ?15 GeV/fm3 gt 10 x larger unscreened color
charge density than in a nucleon0.44 GeV/fm3
72
Baier, et al Screened Coulomb potential
MJT ?2 plays role of tmin
ARNPS 50 (2000) 37
...
transport coefficient ? mean 4-momentum
transfer2/mean free path
?? 0.5 GeV/c1/0.4 fm
73
Status of RAA in AuAu at ?sNN200 GeV QM05
Direct ? are not suppressed. ?0 and ? suppressed
even at high pT Implies a strong medium effect
(energy loss) since ? not affected. Suppression
is flat at high pT. Are data flatter than theory?
74
Charm via direct single e in p-p collisions
PHENIX PRL97(2006)252002
Beautiful agreement of e? with c b production in
p-p
75
In AuAu, total production of charm is pointlike
but pT spectrum shows suppression

• not only high pT ?0 from light quarks and
  gluons but also very heavy quarks lose energy
  trying to escape system very opaque

• total charm yield determined from integral of
  single electron spectrum
• charm decay dominant source of intermediate pT
  electrons

PRL 98, 172301 (2007)
PRL 94, 082301 (2005)
76
QM2006-Direct e? in AuAu indicate a theoretical
crisis
AuAu
p-p
p-p beautiful agreement of e? with c b
production PHENIX PRL97(2006)252002
AuAu PHENIX PRL 98 (2007)172301
? heavy quarks suppressed the same as light
quarks, and they flow, but less. ?
This disfavors the hypothesis of energy loss by
gluon bremsstrahlung in medium ? but brings
string theorists into the game, see references in
PRL 98 (2007) 172301.
77
Correlations
e.g. p p ? jet jet c.f.
Au Au ? jet jet
78
Away side correlations in AuAu much wider than
in p-p
D
Away side distribution much wider in AA than p-p
in correlation fn. C(??) Subtraction of v2
(flow?) effect? J(??) causes a dip at 180o which
gives 2 peaks at ??D1 radian independent of
system and centrality for Npart gt100. This is
also seen for (auto) correlations of low pT
particles. Is this the medium reaction to the
passage of a color-charged parton? Why no
dependence on centrality? Stay tuned, much more
study needed.
79
New PHENIX AuAu PRC 77,011901(R)(2008)
Away side correlation in AuAu is generally wider
than p-p with complicated structure
Define Head region (HR) and Shoulder regions (SR)
for wide away side correlation.
80
Away-side yield vs xE?pTa/pTt is steeper in
AuAu than p-p indicating energy loss AND learn
something new in p-p
The away side pTa/pTt ? xE distribution triggered
by a leading particle with pTt was thought to be
equal to the fragmentation function but we found
that it is NOT sensitive to the shape of the
fragmentation function but only to the shape of
the inclusive pTt spectrum with power n (8.1).
Formula derived in PRD 74 (2006) 072002 works for
pp and AA
h?(4ltpTtlt5 GeV/c)--h?
PHENIX AuAu PRC 77, 011901(R)(2008)
81
STAR dAu, AuAu
82
For 5ltpTtlt10 GeV/c punch-thru is clear in both
IAA and fit to dP/dxE in PHENIX
??26.2/1 Np/Npp0.27?0.08
2 component fit shows 27 punch-thru, much larger
energy loss 77
83
Punch-thru and normal fragmentation of parton
which has lost energy are standard features
e.g ZhangOwensWangWang PRL 98 (2007) 212301
scaled frag f of c
radiates
frag f of radiated g
punch-thru with poisson probability
Even with ltL/?gt3, probability of punch-thru is 5
84
Yet many believe that punch-through is due only
to tangential emission from an opaque medium
Tangential emission
why does it depend on pT?
We must carefully map out how this effect depends
on pTt and pTa and particle type and angle to the
reaction plane.
Correlations with direct-? can also resolve this
issue.
85
Direct e? in AuAu indicate a theoretical crisis
AuAu PHENIX PRL 98 (2007)172301
Run-7
? heavy quarks suppressed the same as light
quarks, and they flow, but less. ?
This disfavors the hypothesis of energy loss by
gluon bremsstrahlung in medium ? BUT--There are
other very fundamental ideas which could explain
the effect
86
New-J/? at large pT-small contribution to Direct
(Heavy Flavor) e?
Insignificant change! A.Dion QM09 0907.4749
87
Slightly Better agreement with Theory in p-p but
still major crisis in AuAu
88
From CERN Courier, September 2007

• I read an article Yukawa's gold mine by Nino
  Zichichi taken from his talk at INPC 2007 in
  Tokyo, Japan, in which he proposed We know that
  confinement produces masses of the order of a
  GeV. Therefore, according to our present
  understanding, the QCD colourless condition
  could not explain the heavy quark mass. However,
  since the origin of the quark masses is still not
  known, it cannot be excluded that in a QCD
  coloured world (i.e. QGP), the six quarks are all
  nearly massless and that the colourless condition
  is flavour dependent.
• MJT Wow! Massless b and c quarks in a
  color-charged medium would be the simplest way to
  explain the apparent equality of gluon, light and
  heavy quark suppression indicated by the equality
  of RAA for ?0 and direct-single e in regions
  where both c and b quarks dominate.

89
Why would I be so quick to believe Zichichi?
Proc. 12th ICHEP, Dubna 1964
90
In my opinion Zichichis idea is much more
reasonable than AdS/CFT! How to prove it?
First, comments from some distinguished
physicists

• Stan BrodskyOh, you mean the Higgs Field cant
  penetrate the QGP.
• Rob Pisarski You mean that the propagation of
  heavy and light quarks through the medium is the
  same
• Chris Quigg (Moriond 08) The Higgs coupling to
  vector bosons ?, W, Z is specified in the
  standard model and is a fundamental issue. One
  big question to be answered by the LHC is whether
  the Higgs gives mass to fermions or only to gauge
  bosons? The Yukawa couplings to fermions are
  put in by hand and are not required. What sets
  fermion masses, mixings?

91
Does this affect the mW-mt-mH relationship?

• Bill Marciano No change here if no Yukawa
  coupling but there could be other changes (?)

92
My Proposaluse the VTX to be installed in 2010

• Map out, on an event-by-event basis, the
  di-hadron correlations from identified
  di-jets, identified di-jets, and light
  quark and gluon di-jets, which originate from the
  vertex and can be measured with ?0-hadron
  correlations. These measurements will confirm in
  detail (or falsify) whether the different flavors
  of quarks behave as if they have the same mass in
  a color-charged medium.

MJT-Erice08
93
First e?-h heavy flavor correlation-no VTX

• heavy flavor tagged correlations NLO
  important--eHF not necessarily balanced by
  back-to-back heavy quark

Quark Matter 2009
Anne M. Sickles March
31, 2009
94
Another Good Betting Opportunity at LHC
Will H???- or bb- at the expected SM rate be
found (at LHC) before we can measure b-quark
energy loss at RHIC?
95
Status of RAA in AuAu at ?sNN200 GeV QM09
Exponential enhancement of direct-? as pT?0 is
unique. No other particle is enhanced except in
the region of the baryon anomaly. This suggests
new physics, i.e. thermal photons.
96
Discoveries at RHIC lead to many new
open fundamental questions Some even relevant
to particle physics at LHC
97
References-Review Articles

• M.J. Tannenbaum
• ? Review of hard scattering and jet analysis
  PoS(CFRNC2006)001
• ?Recent results in relativistic heavy ion
  collisions from a new state of matter' to the
  perfect fluid, Rep. Prog. Phys. 69 (2006)
  2005-2059
• ? Heavy Ion Physics at RHIC, Int. J. Mod. Phys
  E17 (2008) 771-801
• PHENIX White Paper
• ?Formation of dense partonic matter in
  relativistic nucleus-nucleus collisions at RHIC
  Experimental evaluation by the PHENIX
  collaboration Nucl.Phys.A757 (2005) 184.
• PHENIX Research Papers
• ?Measurement of High pT Single Electrons from
  Heavy-Flavor Decays in pp Collisions, Phys.
  Rev. Lett. 97 (2006) 252002.
• ?Energy Loss and Flow of Heavy Quarks in AuAu
  Collisions at ?sNN200 GeV, Phys. Rev. Lett. 98
  (2007) 172301.
• Also see others listed on the slides.

98
PHENIX W? ?e? X ?s500 GeV first test run 2009
Left (etotal in cone) vs ecore ( - are
combined) Right ecore dist. Full statistics (10
pb-1)
?Cone size 0.5, (etotal in the cone) (ecore
for e photon) (mom for charged
particle) ?Isolation cut y lt 0.1x 1.0 (black
line in the left plot)
98
99
Jet Reconstruction in p-p and AA at RHIC

• MJT and many ISR veterans at Intl. Workshop on
  QGP Signatures, Oct 1-4, 1990, Strasbourg
  (Editions Frontières) agreed that the measurement
  of jets was difficult in AA collisions but
  Fortunately, the production of high pT single
  particles provides an alternative method to
  detection of the complete jet energy (Lissauer)

100
THE UA2 Jet-Paris 1982
From 1980--1982 most high energy physicists
doubted jets existed because of the famous NA5 ET
spectrum which showed NO JETS. This one event
from UA2 in 1982 changed everybodys opinion.
101
Jet measurements of QCD in pp collisions are now
standard after a 30 year learning curve
The measured crosssection is in agreement with
NLO pQCD predictions after the necessary
nonperturbative parton-to-hadron correction sare
taken into account.
A. Abulencia, et al, CDF PRL 96 (2006) 122001-kT
algorithm
At RHIC, inclusive single particles provide a
precision pQCD probe, well calibrated in pp, dAu
collisions
102
BDMPS 1997-1998

• In 1998 at the QCD workshop in Paris, Rolf Baier
  asked me whether jets could be measured in AuAu
  collisions because he had a prediction of a QCD
  medium-effect on colored partons in a
  hot-dense-medium with lots of unscreened color
  charge.
• As the expected energy in a typical jet cone

is ? R2 x1/ 2? x dET/d? R2/2 x dET/d? 300 GeV
for R1 at ?sNN200 GeV where the maximum Jet
energy is 100 GeV, Jets can not be reconstructed
in AuAu central collisions at RHIC.
103
STAR Jet measurement in p-p collisions---first
at RHIC-hep-ex/0608030
Jets were reconstructed using a midpoint-cone
algorithm
See Kilgore, Giele PRD55 (1997) 7183 for a
critical review of jet algorithms
104
Non-Random Fluctuations of ET measured in PHENIX
(a nice jet cone) 1 in AuAu
compare Data to Mixed events
Random Fluctuations 5-875-120 GeV
Are the fluctuations identical in adjacent
patches of R1 ?
105
STAR-Jet in AuAu-suppressed?
106
I think this figure contradicts conclusion in
previous figure!
107
First Jet Reconstruction in PHENIX p-p
108
PHENIX CuCu Event Display

• Event display of two CuCu events
• Di-jet event
• Single-jet event, other outside acceptance (?)

109
Two methods to calculate CuCu effect on jet pT
110
CuCu Jet RAA compared to ?0

• Jet RAA comparable to p0 RAA but extends to much
  larger pT. If true, suggests the medium effect
  persists to higher pTgt 20 Gev/c--Good for LHC
• Is this physics or due to the algorithm missed
  out of cone radiation, collisional energy loss,
  size of filter region, size of detector, other ?
  We dont know yet.

111
Jets in Hadron Collisions are very complicated
with a long learning curve. Probably worse in RHI
physics. I think that hard scattering is better
learned with single particle and few particle
correlation measurements. The main advantage of
jets is rate at large pT
112
Totally new and Unique in RHI collisions--if
correct!
113
Chern-Simons-Karzeev
turn Large static B field into E field-I
114
Chern-Simons-Karzeev
turn Large static B field into E field-I
115
Chern-Simons-Karzeev
turn Large static B field into E field-I
116
AuAu and CuCu 200 vs 62 GeV
200 GeV
62 GeV
/ signal at lower energy is stronger, qualitati
vely in agreement with theory Uncertainties
due to non-RP effects arenot shown!
A practical approach three particle correlations
Voloshin-STAR-QM09-0907.2213
MJT comment-should do with pp for a baseline
since effect increases with decreasing centraliy
and lighter nuclei.
QM2009 Experimental
study of spontaneous strong parity violation
S.A. Voloshin
page
116