Critical Examination of RHIC Paradigms-mostly high p T

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Paradigms 2010 M. J. Tannenbaum 1 /60/65/77 Critical Examination Critical Examination of RHIC Paradigms- of RHIC Paradigms- mostly high p mostly high p T T M. J. Tannenbaum Brookhaven National Laboratory Upton, NY 11973 USA Workshop on “Critical Examination of RHIC Paradigms” The University of Texas At Austin Austin, Texas, USA April 16, 2010

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Critical Examination of RHIC Paradigms-mostly high p T. M. J. Tannenbaum Brookhaven National Laboratory Upton, NY 11973 USA. - PowerPoint PPT Presentation

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Page 1: Critical Examination of RHIC Paradigms-mostly high p T

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Critical Examination of RHIC Critical Examination of RHIC Paradigms-mostly high pParadigms-mostly high pTT

M. J. TannenbaumBrookhaven National Laboratory

Upton, NY 11973 USA

Workshop on “Critical Examination of RHIC Paradigms”

The University of Texas At Austin Austin, Texas, USA

April 16, 2010

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The Quark Gluon Plasma (The Quark Gluon Plasma (QQGGPP))• The QQGGPP should be in chemical (particle type) and thermal equilibrium <pT> ~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.

One paradigm that I don’t believe is that one can find the critical point by an energy scan at RHIC: Luciano Moretto says, “critical fluctuations depend on a first order phase transition below the critical point whose large fluctuations drive the critical fluctuations” i.e. is all the interesting physics just outside the E802 aperture?

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Given the Given the QQGGPP, what is my interest?, what is my interest?The QQGGPP is the only place in the universe where we can in principle and in practice understand QQCCDD for color-charged quarks in a color charged medium. How long will it take before we understand this as well as we understand a muon in Cu in QED?

slide by Jamie Nagle from PDG following a discussion with me.

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QED Bremsstrahlung in matter and XtalsQED Bremsstrahlung in matter and Xtals• Even for such a seemingly simple reaction as muon bremsstrahlung, there is no simple formula: e.g. see• Apart from the LPM effect, there are also very interesting effects of electron bremsstrahlung in a solid: coherent Brems in a Xtal which increases the radiation; LPM effect which decreases the radiation at low x=k/E; and a medium effect on the forward outgoing photon from Compton scattering off the atomic electrons which if inside the coherence length, kills the dN/dk=1/k divergence. The coherence length is set by tmin.

1

Lcoh

= qL = tmin =m2k

2E(E − k)

Bethe Heitler:

kdN

k=

t

Xo

LPM

Medium- “Dielectric”

P. Amaral, et al, ATLAS TileCal Collab, EPJC 20(2001)487

P.L.Anthony, et al PRD56(1997)1373

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Coherent Brems in Diamond-from Texas-SSCCoherent Brems in Diamond-from Texas-SSC

MJT-Coherent photon beam from 10 TeV electrons at SSC--Fixed Target Workshop, The Woodlands TX, Jan 26-30, 1984 (based on original code from Roy Schwitters)

Rudolf Baier requests preprint BNL-34614 from MJT

dE/dx in QCD in a QGP is much more complicated than in QED. We have barely scratched the surface.

Coherent peak at k=9.48 TeV from 10 TeV e

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They were searching for the W boson.

Why were some people studying “high Why were some people studying “high ppTT”physics in the 1960’s?”physics in the 1960’s?

• The first opportunity to study weak interactions at high energy was provided by the development of neutrino beams at the new accelerators in the early 1960’s CERN-SpS , BNL-AGS.

• However, it was soon recognized that the intermediate (weak) boson W, might be more favorably produced in nucleon-nucleon collisions.

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The ‘Zichichi signature’ for the W bosonThe ‘Zichichi signature’ for the W bosonProc. 12th ICHEP, Dubna 1964

UA1,UA2, CERN 1983 W boson discovery

PHENIX+STAR 4.0 Parity Violation

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Searches for W boson in p-p collisionsSearches for W boson in p-p collisions

• 1965-1969 Beam dump experiments at ANL-ZGS and BNL-AGS looking for “large angle” muons didn’t find any. [ZGS-Lamb, et al PRL 15, 800 (1965), AGS-Burns, et al, ibid 830, AGS-Wanderer et al, PRL 23,729(1969)]

• How do you know how many W should have been produced?

• Chilton, Saperstein, Shrauner [PR148, 1380 (1966)] emphasize the importance of the timelike form factor, which is solved by

• Y. Yamaguchi [Nuovo Cimento 43, 193 (1966)] Timelike form factor can be found by measuring the number of lepton pairs e+e- or +- “massive virtual photons” of the same invariant mass; BUT the individual leptons from these electromagnetically produced pairs might mask the leptons from the W.

• This set off a spate of single and di-lepton experiments, notably the discovery by Lederman et al of “Drell-Yan” production at the BNL-AGS, E70 at FNAL and CCR at the CERN-ISR.

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AGS-1969-71 Discovery of ‘Drell-Yan’ and ??AGS-1969-71 Discovery of ‘Drell-Yan’ and ??

Christenson, Lederman…PRL 25, 1523 (1970) `Theory’ Altarelli, Brant Preparata PRL 26 42 (1971)

p+U+-+X

sNN=7.4 GeV

This is why I NEVER plot theory curves on any of my data

long forgotten

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LML very excited in 1970: AGS-diLML very excited in 1970: AGS-di continuum continuum +Bj scaling+Bj scalingW cross section at any W cross section at any ss

From Proposal E70 at FNAL

E70-(F)NAL

yield exp -6pT

worst imaginable background

can suppress by 103

pT=MW/2

+ addendum Dec 1970

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?? explained by J/?? explained by J/ in 1974 at AGS + SLAC in 1974 at AGS + SLAC

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The whole truth--‘Applied HEP’The whole truth--‘Applied HEP’

NA50 PLB 477, 28 (2000)

E70 PRL 39 252 (1977)

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The gold-plated signature for the The gold-plated signature for the QQGGPPJ/J/ Suppression Suppression

• In 1986, T. Matsui & H. Satz PL B178, 416 (1987) said that due to the Debye screening of the color potential in a QQGGPP, charmonium production would be suppressed since the cc-bar couldn’t bind.

• This is CERN’s Heavy Ion’s claim to fame: but the situation is complicated because J/ are suppressed in p+A collisions. [NA50 collaboration, M.C. Abreu, et al., PLB 477, 28 (2000)]

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How to discover the QGP-1990-91How to discover the QGP-1990-91• The Classical road to success in RHI Physics: J/ Suppression

• 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---> 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

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The first paradigm change:BDMPS 1997-1998The first paradigm change:BDMPS 1997-1998In 1998 at the QCD workshop in Paris, Rolf Baier asked me whether jets could be measured in Au+Au 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 R=1 at sNN=200 GeV where the maximum Jet energy is 100 GeV, Jets can not be reconstructed in Au+Au central collisions at RHIC.

R = (Δη )2 + (Δφ)2

But hard-scattering can be well studied by single inclusive and 2-particle correlation measurements as it was discovered at the CERN ISR in the 1970’s: “Everything you want to know about JETS can be measured with two particle correlations.”

And it just so happened that the PHENIX detector was designed to trigger, measure and separate and 0 out to pT> 25 GeV/c !

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Three things are dramatically different in Three things are dramatically different in Relativistic Heavy Ion Physics Relativistic Heavy Ion Physics

than in p-p physicsthan in p-p physics• the multiplicity is ~A~200 times larger in AA central collisions than in p-p huge energy in jet cone: 300 GeV for R=1 at sNN=200 GeV• huge azimuthal anisotropies which don’t 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?

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Example of space-time issuesExample of space-time issues

• When in time and space does a parton fragment? Is this different for light and heavy quarks? When are particles formed?

• Dokshitser textbook formula: F=ER2 tF=R=ER/M=ERc

• Would a proton embedded in a QQGGPP dissolve? How long does this take? How is this related to J/Psi suppression?

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00's in p+p 's in p+p s=200 GeV: Data vs. pQCDs=200 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

Inclusive invariant 0 spectrum is pure power law for pT≥3 GeV/c n=8.1±0.1

Hard Scattering -- varies with s

p-p

Thermally-shaped Soft Production: e-6pT indep.

s

NLO-pQCD described very well

down even to pT ~ 1 GeV/c

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Soft Physics Dominates Soft Physics Dominates Particle production Particle production

in both p-p and A+A in both p-p and A+A (Relativistic Heavy Ion) (Relativistic Heavy Ion)

collisionscollisions

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4%

0.5%

c0 Bj =5.40.6 GeV fm-2

PRC 71 (2005) 034908

AuAu Central Collisions cf. p-pAuAu Central Collisions cf. p-pSTAR-Jet event in pp STAR Au+Au central

High pT particle

p+p

High pT particle

Au+Au

PHENIX Au+Au central

Bj =1

πR2

1

cτ 0

dET

dy

⎝ ⎜

⎠ ⎟

per unitvelocity || to beam

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4%

0.5%

p+p RHIC

Au+Au EAu+Au ETT spectra at AGS and RHIC are the same shape!!! spectra at AGS and RHIC are the same shape!!!

/8 0.76/4 0.76

3/8 0.76/2 0.76

5/8 0.76

16003200 LHC ?

Bj =1

πR2

1

cτ 0

dET

⎝ ⎜

⎠ ⎟

PRC 71 (2005) 034908

c0 Bj =5.40.6 GeV fm-2

i.e no critical fluctuations

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Paradigm we should do away withParadigm we should do away with

Although it may be sensible for the average it makes no sense for the distribution which would look like the weighted sum of the Npart + Ncoll curves, which looks nothing like the actual distribution

AA

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a soft physics question for the LHCa soft physics question for the LHC

• Will the QGP at the LHC be a superfluid like the liquid He coolant in the magnets?

•[H. Song and U. Heinz Phys. Rev. C78 (2008) 024902] : viscous hydro is more sensitive to /s than to the peak energy density e0, so v2 shouldn’t change much 15-20% from RHIC to LHC. [Busza-Last Call LHC] extrapolation of measured v2 vs sNN predicts an increase by a factor of 1.6 from RHIC to LHC. Will this be the failure of hydro? Another paradigm about to fall soon?

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Now, Back To Now, Back To Hard-ScatteringHard-Scattering

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Timeline of hard-constituent ScatteringTimeline of hard-constituent Scattering• 1968--Deeply Inelastic scattering of electrons on protons observed at SLAC. First direct indication of sub-constituents of proton, “partons” as explained by Bjorken scaling [J.D. Bjorken, Phys. Rev. 179, 1547 (1969)]

• 1971--High pT scattering of “partons” via QED predicted for p-p collisions by Bjorken, Berman, Kogut [BBK, Phys. Rev. D4, 3388 (1971)]

• 1972 First evidence of hard-scattering of constituents discovered at CERN ISR--attention turns from spectroscopy to “high pT physics”

• 1974--J/ discovered at BNL and SLAC-people start believing that partons are real and are the same as quarks.

• 1972-1982 properties of hard-scattering and “Jets” mapped out at CERN-ISR for a decade 1975,1977-78 first theory papers on QCD applied to hard-scattering

• 1982-Constituent-scattering Angular distribution measured at ISR in agreement with QCD. (Rutherford scattering of quarks). SppS (UA2)- first observation of unbiased Jets in hadron collisions.

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Bjorken Scaling in Deeply Inelastic Bjorken Scaling in Deeply Inelastic Scattering and the Parton Model---1968Scattering and the Parton Model---1968

ν =Q2

2Mx

Phys. Rev. 179, 1547 (1969)

Phys. Rev. 185, 1975 (1969)

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BBK 1971BBK 1971S.M.Berman, J.D.Bjorken and J.B.Kogut, Phys. Rev. D4, 3388 (1971)

• BBK calculated for p+p collisions, the inclusive reaction

A+B C + X when particle C has pT>> 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.”

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CCR at the CERN-ISRCCR at the CERN-ISRDiscovery of high pDiscovery of high pTT 00 production in p-p production in p-p

• e-6pT breaks to a power law at high pT with characteristic s dependence• Large rate indicates that partons interact strongly (>> EM) with other.• Data follow xT=2pT/s scaling but with neff=8!, not neff=4 as expected for QED

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 xT=2pT/s Scaling PL 42B, 461 (1972)

neff gives the form of the force-law between constituents: neff=4 for QED

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CCOR 1978--Discovery of CCOR 1978--Discovery of “REALLY high p“REALLY high pTT>7 GeV/c” at ISR>7 GeV/c” at ISR

CCOR A.L.S. Angelis, et al, Phys.Lett. 79B, 505 (1978)

neff=5 (=4++) as predicted for QCD

QCD: Cahalan, Geer, Kogut, Susskind, PRD11, 1199 (1975)

8

5

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1978-n1978-neffeff(x(xTT, , s) WORKS ns) WORKS neffeff5=45=4++++

C.Kourkoumelis, et al Phys.Lett. 84B, 279 (1979)

cross sections vary by factor of 2

But n(xT,s) agrees

A.Adare, et al, PHENIX PRD79 (2009) 012003

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CCRS-1974 Discovery of direct CCRS-1974 Discovery of direct ee~10~10-4-4 at ISR at ISR not due to internal conversion of direct photonsnot due to internal conversion of direct photons

CCRS PLB53(1974)212; NPB113(1976)189 Data points (e++e-)/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 e+e- (d/dm~1/m) for pT>1.3 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

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J/Psi and direct J/Psi and direct ee

CSZ NPB142(1978)29 pT=1.100.05 GeV/c

CCRS NPB113(1976)189 direct e not due to J/

First Best Not cause of direct e

CCRS PLB56(1975)482 2nd J/ in Europe

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Correlations pTtrig>6 GeV/c

ISR direct photon production + correlationsISR direct photon production + correlationsQCD Fritzsch and Minkowski, PLB 69 (1977) 316-320--ISR discovery R806-A2BC-PLB 87(1979)292.

q

qg

q

q g

isolatedphotonsCompton

Annihilation

Cross Section

/0

No evidence for bremss. contribution to direct --same side correlation is zero--see CMOR NPB327, 541 (1989) for full list of references.

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Status of ISR single particle Status of ISR single particle measurements 1978measurements 1978

kT is what made n=4++ n=8

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Status of QCD Theory in 1978Status of QCD Theory in 1978• The first modern QCD calculation and prediction for high pT single particle inclusive cross sections including non-scaling and initial state radiation was done in 1978 by J. F. Owens, E. Reya, M.Gluck, PRD 18, 1501 (1978), “Detailed quantum-chromodynamic predictions for high-pT processes,” and J.F. Owens, J. D. Kimel, PRD 18, 3313 (1978), “Parton-transverse-momentum effects and the quantum-chromodynamic description of high-pT processes”.

• This work was closely followed and corroborated by Feynman, Field, Fox PRD 18, 3320 (1978), “Quantum-chromodynamic approach for the large-transverse-momentum production of particles and jets.”

• Unfortunately jets in 4 Calorimeters at ISR energies or lower are invisible below GeV, which led to considerable confusion in the period 1980-1982.

ˆ s ≈ ET ≤ 25

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QQCCDD and Jets and Jets are now a cornerstone of the standard modelare now a cornerstone of the standard model

• Incredibly at the famous Snowmass conference in July 1982, many if not most people in the U.S. were skeptical

e.g. MJT Seminar in 1982

• The International HEP conference in Paris, three weeks later, July 26--31, 1982 changed everything.

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At the CERN ISR from At the CERN ISR from 1975-1982 two-particle 1975-1982 two-particle

correlations showed correlations showed unambiguously unambiguously

that high pthat high pTT particles come particles come

from jetsfrom jets

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How everything you want to know about JETS How everything you want to know about JETS was measured with 2-particle correlationswas measured with 2-particle correlations

CCOR, A.L.S.Angelis, et al Phys.Lett. 97B, 163 (1980) PhysicaScripta 19, 116 (1979)

pTt > 7 GeV/c vs pT

xE pTt

pout=pT sin

pTt pT

Away side pout~pT is not constant i.e 1/pT, indicating jets not collinear in azimuth kT

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xxEE distribution measures fragmentation fn. distribution measures fragmentation fn.

Dq(z)~e-6z

independent of pTt

<ztrig>=0.85 measured

Regarding CDF PRD79,112005, this plot from 1979 showed that there were NO di-jets each of a single particle as claimed by another ISR exp’t (p511) since there was no peak at xE=1

See M. Jacob’s talk Proc. EPS 1979 Geneva (CERN). p512

At RHIC we learned that the xE distribution from a trigger fragment does not measure the fragmentation function.

xE ~ z/<ztrig>same data (pTt>7 GeV/c)

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Where did I (and everybody in HEP) get Where did I (and everybody in HEP) get this idea?---from Feynman, Field and Foxthis idea?---from Feynman, Field and Fox

“There is a simple relationshipbetween experiments done with single-particle triggers and those performed with jet triggers. The only difference in the opposite side correlation is due to the fact that the ‘quark’, from which a single-particle trigger came, always has a higher p than the trigger (by factor 1/ztrig). The away-side correlations for a single-particle trigger at p should be roughly the same as the away side correlations for a jet trigger at p (jet)= p (single particle)/ <ztrig>”.

FFF Nucl.Phys. B128(1977) 1-65

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THE UA2 Jet-Paris 1982THE UA2 Jet-Paris 1982From 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 everybody’s opinion.

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CCOR Jets after 8 orders of mag. PL 126B, 132 (1983)

Also Paris 1982-Jets in EAlso Paris 1982-Jets in ETT distribution distribution

NA5-1980 ICHEP-No Jets 7 orders of magnitude

s=24.3 GeV

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LO-LO-QQCCDD in 1 sli in 1 sliddee

A

B

a

bc

d

C

faA (x1) D cC /

fbB (x2) D dD /

dˆ t X

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DATA: CCOR NPB 209, 284 (1982)

Also Paris1982-first measurement of QCD Also Paris1982-first measurement of QCD subprocess angular distribution using subprocess angular distribution using 00--

00 correlations correlations

QQCCDD

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British French Scandinavian “Ridge”British French Scandinavian “Ridge”

Split Field magnet, horrible magnetic field uniformity. Track recon took ~5 yrs to develop + 1 hour of CDC7600 per hour of data! Great acceptance when it finally worked. BFS

NPB145(1978) 308

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For the past decade these For the past decade these single and two-particle single and two-particle techniques were used techniques were used

exclusively at RHIC for exclusively at RHIC for hard-scattering, with hard-scattering, with outstanding results...outstanding results...

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19% norm uncertainty

p-p collisions at RHIC: p-p collisions at RHIC: 00 production (PHENIX) production (PHENIX)

e−5.6 pT

No surprise (to me) that NLO pQCD agrees with dataPRD76(2007)051006(R)

s=200 GeV

hard component is difference between exp-5.6pT and data

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ISR ISR 00 vs RHIC p-p vs RHIC p-p RHIC pp vs AuAu RHIC pp vs AuAu

p-p

0 invariant cross section in p-p at s=200 GeV is a pure power law for pT > 3 GeV/c, n=8.10.1

Nuclear Modification Factor

0 are suppressed in Au+Au eg 200 GeV

RAA ( pT ) =d2NAA

π /dpT dyNAAinel

TAA d2σ ppπ /dpT dy

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The baryon anomaly is not due to recombinationThe baryon anomaly is not due to recombination

ps: If this is ‘recombination’ QGP: Fries,Muller, Nonaka PRL 90 202303 (2003)

PHENIX PRL 91 (2003) 172301

p/ ratio much larger than from jet fragmentation or bulk: The Baryon

Anomaly-still not understood

Trigger mesons and baryons in the region of the baryon anomaly both show the same trigger (near) side and away side jet structure. This ‘kills’ the elegant recombination model of the baryon anomaly.

PHENIX PLB 649 (2007) 359

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RRAAAA 00 in AuAu in AuAu ssNNNN=200 GeV vs. Reaction Plane =200 GeV vs. Reaction Plane to probe details of the theory-learn something new!to probe details of the theory-learn something new!

L

Phys Rev C 76, 034904 (2007)

Phys Rev C 80, 054907 (2009)

Little/no energy loss for L < 2 fm

L = distance from edge to center of participants calculated in Glauber model

RAA is absolute, v2 is relative so no hint of this in v2 measurements. This result also suggests that v2 for pT>2GeV/c is due to anisotropic energy loss not flow.

RAA() vs. centrality varies density of and distance through medium

3 < pT < 5 GeV/c

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pid measurements in p+p: mesons, pid measurements in p+p: mesons, , jet , jet

If you want to measure jets for best rate at large pT [where effects of medium may be negligble], fine, but don’t forget the many other probes [with precise pT scales!!!] in the 0-20 GeV/c pT range (which is likely more interesting).

PHENIX PLB 670 (2009) 313 +STAR has lots of hyperons

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Status of RStatus of RAAAA in AuAu at in AuAu at ssNNNN=200 GeV QM09=200 GeV QM09

Exponential enhancement of direct- as pT0 is unique. No other particle is enhanced except in the region of the ‘baryon anomaly’. This suggests new physics, i.e. thermal photons.

particle ID is crucial different particles behave differently

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CorrelationsCorrelations

e.g. p + p e.g. p + p jet + jet c.f. Au + Au jet + jet c.f. Au + Au jet + jet jet + jet

Au+Au

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PHENIX AuAu PRC PHENIX AuAu PRC 7777,011901(R)(2008) ,011901(R)(2008)

Define Head region (HR) and Shoulder regions (SR) for wide away side correlation.

Away side correlation in Au+Au is generally wider than p-p with complicated structure

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STAR dAu, AuAuSTAR dAu, AuAuSTAR-PRL 97 (2006) 162301

8 < pTt < 15 GeV/c

STAR-PRL95(2005)152301

4 < pTt < 6 GeV/c

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Newer STAR-Horner-QM2006-JPG34 (2007) S995Newer STAR-Horner-QM2006-JPG34 (2007) S995

Two-component distribution (punch-through) is now clear for 6< pTt< 10 GeV/c

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2 component fit to dP/dx2 component fit to dP/dxEE c.f. I c.f. IAAAA

component 1: N, free; second component Np free: Np/Npp=IAA=const

ˆ x h = ˆ x hpp

ˆ x h

punch-thru component not statistically significant for 4<pTt< 5 GeV/c

Head |-|</6 Shoulder /6< |-|</2

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For 5<pFor 5<pTtTt<10 GeV/c punch-thru is clear <10 GeV/c punch-thru is clear

in both Iin both IAAAA and fit to dP/dx and fit to dP/dxEE

2=6.2/1 Np/Npp=0.270.08

ˆ x h / ˆ x hpp = 0.23 ± 0.12

2 component fit shows 27% punch-thru, much larger energy loss 77%

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Punch-thru and normal fragmentation of parton Punch-thru and normal fragmentation of parton which has lost energy are standard featureswhich has lost energy are standard features

e.g ZhangOwensWangWang PRL 98 (2007) 212301

radiates

scaled frag f of c

frag f of radiated g

punch-thru with poisson probability

Even with <L/>=3, probability of punch-thru is 5%

The LPM energy loss acts discretely; but BH energy loss, elastic energy loss and multiple scattering with transport coeff should be seen in punch-thru, right?

ˆ q

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No paradigm for wide jet correlations in AuAuNo paradigm for wide jet correlations in AuAu

• Mach cone due to medium reaction. But effect vanishes for larger pTt, no dependence on centralityunlikely expl. PID might show whether composition of shoulder is same as jet or medium for low pTa

• Fluctuations of v3 (Sorensen-arXiv:0808.0503): <v3>=0 at mid rapidity but <(v3)2>0. Gives best fits, consistent with vanishing at large pTt.

• NLO 3-jet events less suppressed than di-jets due to smaller path length in medium (Ayala, Jalilian-Marian..PRL104 (2010)042301)

• ??

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Direct Direct - h - h correlations in p+p correlations in p+p s=200 GeV s=200 GeV PHENIX preliminary resultPHENIX preliminary result

0 Direct q

qg

q

q g

Compton

Annihilation

In order to understand whether away side xE distribution from a direct is the (quark) fragmentation function must understand whether b= 8.2. Must also understand kT smearing for direct .

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Prediction of Jet shape in vacuum and mediumPrediction of Jet shape in vacuum and medium

Would be much easier to understand if they also plotted z in addition to =ln(1/z): e.g =3.0z=0.050

Borghini & Wiedemann, hep-ph/0506218

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Following Borghini & Wiedemann, hep-ph/0506218

Improving on Borghini & Wiedemann, hep-ph/0506218

xxEE distribution from direct- distribution from direct--h does measure -h does measure (quark) fragmentation function (quark) fragmentation function

=ln(1/z)

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direct-direct--h in A+A vs -h in A+A vs 00-h -h

• For -h: Away partons are either totally absorbed or emitted from surface with normal fragmentation fn, same as parton from single particle inclusive: IAA(xE)=constant=fraction not absorbed=RAA(h)

• For 0-h: Only tangential are seen IAA=const=fraction of surface emission that is tangent to surface < RAA(h)

• -h: Away partons lose energy, some punch-thru or are tangent: IAA=constant at larger xE (punchthrough), increases towards xE=0 for partons with energy loss.

• 0-h: Roughly the same except away partons may lose more energy due to surface bias of the trigger, and fewer may punch through

•Totally absorbing mediumsurface emission only

• Translucent lossy medium

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Measured IMeasured IAAAA dir- dir--h in Au+Au-h in Au+Au

p+p inv slope: 6.89 0.64

Au+Au inv slope: 9.49 1.37 but

maybe Au+Au--> 6.89 zT>0.4

PHENIX QM09 arXiv:0907.4571 STAR subm PRL arXiv:0912.1871

More typical PHENIX IAA for 0-h arXiv:1002.1077

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I could go on I could go on for hours, butfor hours, but

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EXTRASEXTRAS

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QM2006-Direct eQM2006-Direct e in Au+Au indicate a theoretical crisis in Au+Au indicate a theoretical crisis

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.

p-p beautiful agreement of e with c b production PHENIX PRL97(2006)252002

Au+Au PHENIX PRL 98 (2007)172301

Au+Aup-p

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From CERN Courier, September 2007From 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.”

• Higgs doesn’t give quarks mass• QCD isn’t flavor-blind !!!

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In my opinion Zichichi’s idea is much more In my opinion Zichichi’s idea is much more reasonable than AdS/CFT! How to prove it? reasonable than AdS/CFT! How to prove it?

First, comments from some distinguished physicists:

• Stan Brodsky:“Oh, you mean the Higgs Field can’t 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?”

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Opinions of distinguished physicists, cont’dOpinions of distinguished physicists, cont’d

• I asked Steve Weinberg (4/15/10) whether the standard model would still work in the vector boson sector if the Higgs didn’t couple to Fermions, or the Higgs Yukawa coupling was much smaller than now considered standard; and could this possibly explain the absence of the Higgs detected in the and + - decay modes.

• He didn’t say yes, He didn’t say no.• But he did say that he and Lenny Suskind had a model,

Technicolor, that worked well in the vector boson sector but didn’t give mass to the Fermions.

• Hmm.

b − b

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Does this affect the mDoes this affect the mWW-m-mtt-m-mHH relationship? relationship?

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

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References-Review ArticlesReferences-Review ArticlesM.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 p+p Collisions”, Phys. Rev. Lett. 97 (2006) 252002.

“Energy Loss and Flow of Heavy Quarks in Au+Au Collisions at sNN=200 GeV,” Phys. Rev. Lett. 98 (2007) 172301.

Also see others listed on the slides.