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
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
High energy nuclear physics of the
70’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:
 ( x F , pt )
 incl   0  A
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
CERN- THE SECOND 25 YEARS
Physics Reports, vol. 403-404, December 2004
>1976 – SPS, 400 GeV/c p primary beam
The production of jets in hard parton-parton scattering was not really
studied 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 a
cleaner experimental signature than that of jets (WA77)
 No dedicated experiments on high Pt hadron production (at SPS)
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
CERN WA72 nuclear experiment
M. G. Abreu et al. CERN/EP 84-51, April 1984
30GeV/c
D.S. Barton et al.
PRD 27 (1983) 2580
general
trend
p data do
not fit to
Aα
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Fermilab high Pt nuclear experiment
D. 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
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Aα extrapolation down to pp ?

 A  0  A
pp cross
section lies
below σ0
fit without D
fit with D
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Cronin: relation between α - RAA
d 3
 ( pt )
n
b
E 3  C  (1 pt )  (1  xt )  const  A
dp
from this and the definition of RAA :
185mb

 RPb, Be
Be
pBe
 APb    N coll

    inel
  
 *  pPb 
 
Pb
 ABe    N coll     inel 
When: α=1, <Ncoll(Pb)>=3.75, <Ncoll(Be)>=1.50
(Glauber) R(Pb,Be) = …1.03 ! not too bad
Padova 29 September 2005
Adam Jacholkowski
inel
 hA
 0  A2 / 3
1.66b
Quench-Mini-Workshop
Cronin: α  RpA for K+ at 200 GeV/c
(Only 3 points at 200 GeV/c , more at 400 GeV/c)
 ( pT ,b ) 1
RpA ( pT , b)  A
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Cronin: RHIC – Fermilab comparison
Antreasyan et.al.Phys.Rev.D19(3)1979
PRELIMINARY
qualitative agreement
Padova 29 September 2005
Adam Jacholkowski
p+A sqrt(s)=27.4 GeV
Quench-Mini-Workshop
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 left
for future work, will improve the agreement
further
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
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…
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Where is the jet quenching in Pb-Pb ?
Xin-Nian Wang , hep-ph/9804384,1998
NO EVIDENCE !?
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Reaction operator approach
Gyulassy, Levai, Vitev,
NP B 594(2001) 371
factor ~ 4
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Discovery ! At RHIC !
(2 years after discovery of
QGP at CERN  1:1)
J. D. Bjorken
Fermilab-Pub-82-059-THY
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Central-to-peripheral
nuclear modification factor(s)
RCP ( pt ) 

N coll
P
N coll
C
RCP at RHIC:
 high-pT: parton energy loss
 intermediate pT: baryon/meson
effect (recombination?)
d 2 N C / dpt dy
 2
d N P / dpt dy

RCP at SPS?
 p0 suppressed: energy loss?
WA98, EPJC23 (2002) 225
(see also RAA re-analysis)
d’Enterria, PLB596 (2004) 32

no baryon/meson comparison
RCP
1-6%
22-43%
HIJING
WA98 data
STAR, PRL92 (2004) 052302 + prelim.
Padova 29 September 2005
Adam Jacholkowski
mT - m0 (GeV)
Quench-Mini-Workshop
The (old) SPS RAA/RCP puzzle
Vitev and Gyulassy
PRL 89, 252301 (2002)
WA98, Eur.Phys. J. C23, 225 (2002)
RAA(central)
See also: X. N. Wang,
Phys. Rev. C61, 064910(2000)
RCP
RAA
?
mT-m0(GeV/c2)
• WA98 p0: RAA enhanced, RCP suppressed for central Pb+Pb
• Calculations: with Cronin effect + quenching do not describe data
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
SPS Heavy Ion Data Revisited, but a problem:
At the SPS (√s = 20 GeV) no good p+p->π0/h reference…
D. d’Enterria, nucl-ex/0403055
Vitev-Gyulassy Energy loss with
dNglue/dy = 400-600*
nucl-ex/0504001
* Compared to dNglue/dy = 200-300
in PRL 89 252301 (2002)
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Excitation function of the nuclear
modification factor
SPS
Fixed pt
D'Enterria '05
Padova 29 September 2005
Adam Jacholkowski
Shadowing
Anti
Shadowing
Cronin effect +
nuclear (anti)shadowing
~compensated by
parton energy loss
at SPS !
Quench-Mini-Workshop
NA57
RCP results
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
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 centrality
dependence
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
RCP from NA57 :
PL-B623(2005)17-25
π,K,p
cocktail
Centrality
dependence
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
K0 vs π0 comparison
SPS
RHIC
PHENIX RCP Au-Au 200 GeV
p p
p
Strangeness matters (not only number of valence quarks)
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Strange meson vs strange baryon
SPS vs RHIC
Similar hierarchy but (of course)
a shift by about 0.5 units
meson/baron compatible with the parton coalescence mechanism
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Comparison with the parton energy loss
models
Evidence for parton energy loss at SPS energy
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
Energy evolution: PQM vs NA57 data
PQM
Wang and PQM both consistent with NA57 (factor 2 suppression)
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
NA49 new data at QM05
NA49 talk by A. Lazslo
Qualitative agreement
with NA57 (different
peripheral classes !)
• RCP(baryon)>RCP(meson)
 same systematics as original Cronin data at similar s
 same systematics as RHIC but scaled upward
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
AA di-hadron Φ correlations at SPS


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
width
yield
NA45 peripheral
NA45 central

Padova 29 September 2005
no evidence for suppression of awayside yield
Adam Jacholkowski
Quench-Mini-Workshop
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)
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
The NA57 Collaboration
F. Antinorik, P.A. Bacone, A. Badalàf, R. Barberaf, A. Belogiannia, I.J. Bloodworthe,
M. Bombarah, G.E. Brunob, S.A. Bulle, R. Caliandrob, M. Campbellg, W. Carenag,
N. Carrerg, R.F. Clarkee, A. Dainesek, D. Di Barib, S. Di Liberton, R. Diviàg, D. Eliab,
D. Evanse, G.A. Feofilovp, R.A. Finib, P. Ganotia, B. Ghidinib, G. Grellao, H. Helstrupd,
K.F. Hetlandd, A.K. Holmej, A. Jacholkowskif, G.T. Jonese, P. Jovanovice, A. Juskoe,
R. Kamermansr, J.B. Kinsone, K. Knudsong, V. Kondratievp, I. Králikh, A. Kravčákovái,
P. Kuijerr, V. Lentib, R. Lietavae, G. Løvhøidenj, V. Manzarib, M.A. Mazzonin, F. Meddin,
A. Michalonq, M. Morandok, P.I. Normane, A. Palmerif, G.S. Pappalardof,
B. Pastirčákh, R.J. Platte, E. Quercighk, F. Riggif, D. Röhrichc, G. Romanoo,
K. Šafaříkg, L. Šándorh, E. Schillingsr, G. Segatok, M. Senél, R. Senél, W. Snoeysg,
F. Soramelk, M. Spyropoulou-Stassinakia, P. Starobam, R. Turrisik, T.S. Tveterj,
J. Urbáni, P. van de Venr, P. Vande Vyvreg, A. Vascottog, T. Vikj, O. Villalobos Bailliee,
L. Vinogradovp, T. Virgilio, M.F. Votrubae, J. Vrlakovai, P. Závadam.
a: Athens, b: Bari, c: Bergen, d: Bergen, e: Birmingham, f: Catania, g: CERN,
h: Kosice, i: Kosice, j: Oslo, k: Padova, l: Collège de France, m: Prague,
n: Rome, o: Salerno, p: St. Petersburg, q: Strasbourg, r: Utrecht
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
backup slides
(just in case…)
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
WA77 CERN higher twist experiment
π-Be
150,300
GeV/c
A Belogianni et al.,
Z. Phys. C 69 (1996)235
Padova 29 September 2005
Adam Jacholkowski
…nothing in our data contradicts
the HT estimates following from
QCD sum rules predictions.
Quench-Mini-Workshop
Experimental facts – dAu (pPb) at SPS
T. Alber et al. (NA35), Eur. Phys. J. C 2, 643 (1998)
dAu
pPb
B. Boimska (NA49), PhD thesis,
Warszawa (2004)
d2N(h-)/dpTdy (d+Au)
RdAu =
NColld2N(p-)/dpTdy (p+p)
Similar trend at the AGS:
R. Debbe et al. (BRAHMS)
CINPP proceedings (2005)
Padova 29 September 2005


Increasing suppression with increasing xF
Pattern similar for pions and antiprotons, different for protons
Adam Jacholkowski
Quench-Mini-Workshop
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 mstrips
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
NA57 acceptance
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
NA57 mass signals
L
X
W
L
X+
W+
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
NA57 centrality bins
Pb-Pb 160 A GeV
0 1
2
3
Padova 29 September 2005
4
< Nwound >
160 GeV
40 GeV
Class
 / tot
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
Adam Jacholkowski
Quench-Mini-Workshop
+ modified recombination
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop
CBBO - CERN BIG BANG ORCHESTRA
Acceleration/
Celebration
Padova 29 September 2005
Adam Jacholkowski
Quench-Mini-Workshop