Adam JacholkowskiPadova 29 September 2005 Quench-Mini-Workshop High P T phenomena in h-A and A-A...

Adam JacholkowskiPadova 29 September 2005 Quench-Mini-Workshop

High PT phenomena in h-A and A-A collisions at fixed-target energies

• Pre-HI high energy nuclear physics • Cronin (alias initial state) effect • Early RAA and RCP results from SPS exp. • New (QM05) RCP data of NA57 and NA49 • NA57/WA97 preliminary results on RAA • AA di-hadron Φ correlations (from NA45) • Summary and conclusions


High energy nuclear physics of the70’s – 80’s

Excited nucleon states in nuclei + hypernuclei Interactions of shortly living states (in statu

nascendi) with nucleons Particle multiplication processes: multiplicities Modification of PDF in nuclei (EMC effect) Mass number (A) dependence of the

(inclusive) cross sections:

),(0

tF pxincl A


CERN- THE SECOND 25 YEARS

Physics Reports, vol. 403-404, December 2004

The production of jets in hard parton-parton scattering was not reallystudied at the SPS since, at these energies, the jet structure could not be well resolved from the dominant background of soft processes;this was also the case for the prompt production of mesons at high Pt

expected to proceed via higher twist QCD mechanism and to have acleaner experimental signature than that of jets (WA77)

No dedicated experiments on high Pt hadron production (at SPS)

>1976 – SPS, 400 GeV/c p primary beam


CERN WA72 nuclear experimentM. G. Abreu et al. CERN/EP 84-51, April 1984

30GeV/c

p data donot fit to Aα

generaltrend

D.S. Barton et al.PRD 27 (1983) 2580


Fermilab high Pt nuclear experimentD. Antreasyan, J. W. Cronin et al, Phys. Rev. D19 (1979) 764-778 p beam 200,300,400 GeV/c, θcms≈ 0, targets: p, d, Be, Ti, W Pt = 0.77 – 6.9 GeV/c, particles: π, K, p and antiprotons


Aα extrapolation down to pp ?

pp cross section lies

below σ0

fit with D fit without D

AA 0


Cronin: relation between α - RAA

pPbinel

pBeinel

Pbcoll

Becoll

Be

PbBePb

AA

pbt

nt

N

N

A

AR

Rofdefinitiontheandthisfrom

AconstxpCdp

dE t

*

:

)1()1(

,

)(3

3

When: α=1, <Ncoll(Pb)>=3.75, <Ncoll(Be)>=1.50 (Glauber) R(Pb,Be) = …1.03 ! not too bad

185mb

1.66b

3/20 Ainel

hA


Cronin: α RpA for K+ at 200 GeV/c

(Only 3 points at 200 GeV/c , more at 400 GeV/c)

( , ) 1( , ) Tp bTpAR Ap b


Cronin: RHIC – Fermilab comparison

Antreasyan et.al.Phys.Rev.D19(3)1979

PRELIMINARY

qualitative agreement p+A sqrt(s)=27.4 GeV


Cronin effect - initial state Kt broadening

Ex: Saturating Cronin effect in ultra-relativistic proton-nucleus collisions, G. Papp, P. Lévai and G. Fai, nucl-th/9903012

Data of Antreasyan et al

In conclusions: We are confident that complete NLO calculations, which are leftfor future work, will improve the agreementfurther


HEAVY IONS at CERN SPS

AFTER 1986

Priority to the sensitive probes of QGP (strangeness, J/Ψ etc) +bulk properties: multiplicities, Y- Pt spectra (blast wave), flow…


Where is the jet quenching in Pb-Pb ?

Xin-Nian Wang , hep-ph/9804384,1998

NO EVIDENCE !?


Reaction operator approach Gyulassy, Levai, Vitev,NP B 594(2001) 371

factor ~ 4


Discovery ! At RHIC !(2 years after discovery ofQGP at CERN 1:1)

J. D. BjorkenFermilab-Pub-82-059-THY


Central-to-peripheral nuclear modification factor(s)

RCP at RHIC:

high-pT: parton energy loss

intermediate pT: baryon/meson effect (recombination?)

dydpNd

dydpNd

N

NpR

tP

tC

Ccoll

PcolltCP /

/)(

2

2

1-6%22-43%

WA98 data

HIJING

mT - m0 (GeV)

RC

P

STAR, PRL92 (2004) 052302 + prelim.

RCP at SPS? 0 suppressed: energy loss?

(see also RAA re-analysis)

no baryon/meson comparison

WA98, EPJC23 (2002) 225

d’Enterria, PLB596 (2004) 32


WA98, Eur.Phys. J. C23, 225 (2002)

RA

A(c

entr

al)

mT-m0(GeV/c2)

RAA

RCP

?

The (old) SPS RAA/RCP puzzle See also: X. N. Wang, Phys. Rev. C61, 064910(2000)

Vitev and GyulassyPRL 89, 252301 (2002)

• WA98 0: RAA enhanced, RCP suppressed for central Pb+Pb • Calculations: with Cronin effect + quenching do not describe data


D. d’Enterria, nucl-ex/0403055

nucl-ex/0504001

Vitev-Gyulassy Energy loss with dNglue/dy = 400-600*

At the SPS (√s = 20 GeV) no good p+p->π0/h reference…

* Compared to dNglue/dy = 200-300 in PRL 89 252301 (2002)

SPS Heavy Ion Data Revisited, but a problem:


D'Enterria '05

Excitation function of the nuclear modification factor

Fixed pt

SPS

Cronin effect + nuclear (anti)shadowing~compensated by parton energy loss at SPS !

AntiShadowing

Shadowing


NA57

RCP results


Centrality (in)dependence of correction weights no need of MC corrections

Corrections for acceptance and efficiency calculated by embedding MC particles of given pT and y in real events, at the level of hits

1.0

no centralitydependence


RCP from NA57 : PL-B623(2005)17-25

Centrality dependence

π,K,pcocktail


K0 vs π0 comparison

PHENIX RCP Au-Au 200 GeV

Strangeness matters (not only number of valence quarks)

RHICSPS


Strange meson vs strange baryon

Similar hierarchy but (of course) a shift by about 0.5 units

SPS vs RHIC

meson/baron compatible with the parton coalescence mechanism


Comparison with the parton energy loss models

Evidence for parton energy loss at SPS energy


Energy evolution: PQM vs NA57 data

PQM

from 200 to 17 GeV

Wang and PQM both consistent with NA57 (factor 2 suppression)


NA49 new data at QM05NA49 talk by A. Lazslo

• RCP(baryon)>RCP(meson) same systematics as original Cronin data at similar s same systematics as RHIC but scaled upward

Qualitative agreementwith NA57 (differentperipheral classes !)


RHIC: disappearance of the away-side jet in central collisions SPS? PRL92(2004)032301

qualitatively: similar pattern quantitatively, within these errors:

consistent with acoplanarity broadening

no evidence for suppression of away-side yield

AA di-hadron Φ correlations at SPS

width yield

NA45 peripheral

NA45 central


SUMMARY & CONCLUSIONS

High energy nuclear physics (before HI’s) legacy Cronin effect discovered at Fermilab (missed at SPS) Early SPS high Pt (HI) data, new analysis after discovery of

jet quenching at RHIC WA80, WA98, NA45, NA49 and NA57 high Pt data point to

the non-negligible parton energy loss in the final state, already at sqrt(s) = 17.3 GeV/c

Consistency with the Theory – scaling with dNg/dy SPS quenching data, in principle, less biased by the corona

effect than RHIC (and LHC) data, but Pt range quite limited ( jet tomography not accessible)


The NA57 Collaboration

F. AntinoriF. Antinorikk,, P.A. BaconP.A. Baconee,, A. BadalàA. Badalàff, R. Barbera, R. Barberaff,, A. BelogianniA. Belogianniaa,, I.J. BloodworthI.J. Bloodworthee,, M. BombaraM. Bombarahh,, G.E. BrunoG.E. Brunobb,, S.A. BullS.A. Bullee,, R. CaliandroR. Caliandrobb,, M. CampbellM. Campbellgg, W. Carena, W. Carenagg, ,

N. CarrerN. Carrergg,, R.F. ClarkeR.F. Clarkeee,, A. DaineseA. Dainesekk,, D. Di BariD. Di Baribb,, S. Di LibertoS. Di Libertonn,, R. DiviàR. Diviàgg,, D. EliaD. Eliabb,, D. EvansD. Evansee,, G.A. FeofilovG.A. Feofilovpp,, R.A. FiniR.A. Finibb,, P. GanotiP. Ganotiaa,, B. GhidiniB. Ghidinibb,, G. GrellaG. Grellaoo,, H. HelstrupH. Helstrupdd, , K.F. HetlandK.F. Hetlanddd,, A.K. HolmeA.K. Holmejj,, A. JacholkowskiA. Jacholkowskiff, , G.T. JonesG.T. Jonesee, P. Jovanovic, P. Jovanovicee, A. Jusko, A. Juskoee,,

R. KamermansR. Kamermansrr,, J.B. KinsonJ.B. Kinsonee,, K. KnudsonK. Knudsongg,, V. KondratievV. Kondratievpp,, I. KrálikI. Králikhh,, A. KravčákováA. Kravčákováii,, P. KuijerP. Kuijerrr,, V. LentiV. Lentibb,, R. LietavaR. Lietavaee,, G. LøvhøidenG. Løvhøidenjj,, V. ManzariV. Manzaribb,, M.A. MazzoniM.A. Mazzoninn,,

F. MeddiF. Meddinn,, A. MichalonA. Michalonqq,, M. MorandoM. Morandokk,, P.I. NormanP.I. Normanee,, A. PalmeriA. Palmeriff, G.S. Pappalardo, G.S. Pappalardoff,, B. PastirčákB. Pastirčákhh,, R.J. PlattR.J. Plattee,, E. QuercighE. Quercighkk,, F. RiggiF. Riggiff,, D. RöhrichD. Röhrichcc,, G. RomanoG. Romanooo,,

K. ŠafaříkK. Šafaříkgg,, L. ŠándorL. Šándorhh,, E. SchillingsE. Schillingsrr,, G. SegatoG. Segatokk,, M. SenéM. Senéll, R. Sené, R. Senéll,, W. SnoeysW. Snoeysgg, , F. SoramelF. Soramelkk,, M. Spyropoulou-StassinakiM. Spyropoulou-Stassinakiaa,, P. StarobaP. Starobamm,, R. TurrisiR. Turrisikk,, T.S. TveterT.S. Tveterjj,,

J. UrbánJ. Urbánii,, P. van de VenP. van de Venrr,, P. Vande VyvreP. Vande Vyvregg, A. Vascotto, A. Vascottogg,, T. VikT. Vikjj,, O. Villalobos BaillieO. Villalobos Baillieee,, L. VinogradovL. Vinogradovpp,, T. VirgiliT. Virgilioo,, M.F. VotrubaM.F. Votrubaee,, J. VrlakovaJ. Vrlakovaii,, P. ZávadaP. Závadamm..

a: Athens, a: Athens, b: Bari,b: Bari, c: Bergen,c: Bergen, d: Bergen,d: Bergen, e: Birmingham,e: Birmingham, f: Catania,f: Catania, g: CERN,g: CERN, h: Kosice,h: Kosice, i: Kosice,i: Kosice, j: Oslo,j: Oslo, k: Padova,k: Padova, l: Collège de France,l: Collège de France, m: Prague,m: Prague,

n: Rome,n: Rome, o: Salerno,o: Salerno, p: St. Petersburg,p: St. Petersburg, q: Strasbourg,q: Strasbourg, r: Utrechtr: Utrecht


backup slides

(just in case…)


WA77 CERN higher twist experiment

…nothing in our data contradictsthe HT estimates following from QCD sum rules predictions.

π-Be 150,300GeV/c

A Belogianni et al.,Z. Phys. C 69 (1996)235


Experimental facts – dAu (pPb) at SPS

RdAu =

d2N(h-)/dpTdy (d+Au)

NColld2N(-)/dpTdy (p+p)

Similar trend at the AGS:R. Debbe et al. (BRAHMS)CINPP proceedings (2005)

dAu pPb

Increasing suppression with increasing xF

Pattern similar for pions and antiprotons, different for protons

B. Boimska (NA49), PhD thesis, Warszawa (2004)

T. Alber et al. (NA35), Eur. Phys. J. C 2, 643 (1998)


NA57 Experimental Layout

Target: 1% Pb

Scintillator Petals: centrality trigger

MSD: Multiplicity Silicon Detector

Tracking device: silicon pixel planes (5 x 5 cm2 )

Lever arm: double-sided strips


NA57 acceptance


NA57 mass signals


NA57 centrality bins

Pb-Pb 160 A GeV

0 1 2 3 4

Class / tot < Nwound >160 GeV 40 GeV

0 40 – 53% 62 57

1 23 – 40% 121 119

2 11 – 23% 209 208

3 4.5 – 11% 290 292

4 0 – 4.5% 349 346


+ modified recombination


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Adam JacholkowskiPadova 29 September 2005 Quench-Mini-Workshop High P T phenomena in h-A and A-A...

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