A summary of

1Heavy Ions Meeting – Irfu/SPhN – 17/9/2010

ICHEP

•The French particle physics community is particularly proud to have been selected to host the 35th ICHEP conference in 2010 in Paris. This conference is the focal point of all our field since more than fifty years and is the reference event where all important results in particle physics, cosmology and astroparticles are presented and discussed. This alone sufficed to make this event very important. But in 2010, a coincidence of exceptional events made this conference even more attractive! What is then so special about ICHEP 2010 conference? It was the first ICHEP conference where physics results obtained at the LHC were presented! New results about the elusive Higgs boson, or signals of physics beyond the standard model were therefore expected at this conference! Major discoveries in other domains such as gravitational waves, neutrino telescopes, neutrino oscillations, dark matter or in the flavour sector were also possible, just to name a few.

In addition , 2010 is an important date to shape up the future of our field. Several major projects presented the status of their Conceptual or Engineering Design Reports during the conference. The International Linear Collider (ILC) Global Design Effort team presented the report corresponding to the end of their Technical Design Phase 1. The Compact Linear Collider (CLIC) also reported on its Conceptual Design Report. Other major projects such as Super B factories were also presented. These reports together with LHC physics results will form the basis for key political decisions needed to be taken in the years to come.

In summary, there can be no doubt that Paris was the place to be in summer 2010 for anyone interested in High Energy Physics and we made every effort to make your stay as interesting and enjoyable as possible.

2Heavy Ions Meeting – Irfu/SPhN – 17/9/2010Javier Castillo

ICHEP 2010

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 3

http://www.ichep2010.fr/

That was us, one day out of 3, plus 3 plenary talks

Lesson #1

• If you are interested in Heavy Ion Physics do not go to ICHEP!

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 4

Thanks for your attention!

Lesson #2

• If you don’t speak a fluent pythia, do not go to ICHEP!

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 5

Lesson #3

ALLOCUTION DE M. LE PRÉSIDENT DE LA RÉPUBLIQUE Palais des Congrès de Paris -- Lundi 26 juillet 2010

Madame le Ministre, Mesdames et Messieurs,

Je suis très heureux de pouvoir m'exprimer devant votre assemblée réunie pour la 35ème conférence internationale de la physique des hautes énergies. Vous êtes venus partager vos travaux, vous représentez l'élite

de votre discipline au niveau mondial. Et quelle discipline ! Je ne me lancerai certes pas dans la description détaillée de vos travaux, j'en serais bien incapable, même si je sais à quel point vous incarnez l'essence de la science, son ambition première : repousser les frontières de la connaissance, explorer et cartographier des territoires encore inconnus de la pensée. Il n'y a pas de plus belle aventure humaine que celle que vous vivez au quotidien.

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 6

Outline

• The underlying event (what we call minbias)– LHC

• Heavy Flavour and Quarkonia– RHIC & LHC

• Jets– RHIC

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 7

Off topic – featured guest!

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 88/15

Strangeness enhancement

Compare to NA57 Compare to STAR

Open symbols NA57

Open symbols STAR

NA49 data.Filled symbols are central trigger

T. Anticic

DIE HARD!

THE UNDERLYING EVENT (WE CALL IT MINBIAS)

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 9

Javier Castillo 10

Charged particle multiplicity

•INEL and NSD events in ||<0.5•INEL>1 at least 1 charged particle in ||<1

•increase from 0.9 to 7 TeV ~ 57%

•above Monte Carlo model predictions

arXiv:1004.3514[hep-ph]

M. López NoriegaK. Ulmer

Heavy Ions Meeting – Irfu/SPhN – 17/9/2010

Transverse momentum spectra

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 11

A. Lister

p/p ratio

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•p/p ratio shows no pT (and no rapidity) dependence

•small excess of baryons over antibaryons (asymmetry of ~1.9%) at 900 GeV

•ratio consistent with 1 at 7 TeV, compatible with net-baryon free region

arXiv:1006.5432v1 [hep-ex],accepted for publ. by PRL

Heavy Ions Meeting – Irfu/SPhN – 17/9/2010

M. López NoriegaI. Belikov

Strangeness

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 13

|| < 1 - very good agreement between STAR (200 GeV) and ALICE (900 GeV)- very different from CDF (630/1800) and UA1 (630) for pT > 1.5 GeV- UA1(630) and CDF(630) don’t agree either …to be further investigated (different triggers, acceptance, feed-down correction ?)

Do you remember: large Baryon/Meson ratio at RHIC:parton coalescence from QGP ?K. Ulmer

J. Schukraft

HEAVY FLAVOUR & QUARKONIA

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 14

J/ψ polarization

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 15

Helicity frame

λ>0 transverseλ<0 longitudinal

L. Levy

• no model explains cross section and polarization simultaneously

• many models on the market‣ Color Singlet Model: LO, NLO, NNLO

‣ Color Octet Mechanism: NRQCD... many more

CNM Effects

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 16

NDSG σ = 0,1,2,3,4,…15

EPS08

σ = 0 mb

σ = 4 mb

L. Levy

R. Vogt private communication

arXiv:0912.4498

Ask Elena about this one!

ϒ CNM

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 17

RdA = 0.78 ± 0.28(stat.) ± 0.20(sys.)

L. LevyD. Kikola

More J/ψ mess

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 18

L. LevyD. Kikola

Disagreement at high pT

No suppression at high pT

RAA(pT > 5 GeV/c) = 1.4 ±

0.4 ± 0.2

ϒ RAA

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Au+Au |y|< 0.35

RAA < 0.64 at 90% CL for Upsilon at RHIC.

Who dared to quote it?PHENIX or STAR

L. LevyD. Kikola

Quarkonia @ LHC

Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 20Javier Castillo

J. CastilloG. PassalevaN. LeonardoJ. Kirk

C. Lourenço @ Palaiseau 2010

b cross-section

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A. GolutvinS. Bolognesi

NLO underestimates the cross-section at central η and low pT (very low pT!)

Open Charm

22Heavy Ions Meeting – Irfu/SPhN – 17/9/2010Javier Castillo

Ds+ → Φ π+ → (K+ K-)π+

JETS

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gamma – jets

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 24

rich sample has lower near-side yields compared to those of the 0

different bias Similar medium effect on the away-side of 0 and dir

is this due to tangential emission?

STAR Preliminary

arXiv:0912.1871

Away-side -h:• suppression similar to both RAA and IAA

•similar path as RAA

•quark jet dominated

O. EvdokimovC. Pinkenburg

Away-side -h:• fragmentation function somewhat steeper than p+p (only 1.3σ significance • bpp consistent with quark fragmentation (b=8)

Fragmentation function

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 25

dN/dzT =Ne−bzT

bAuAu = 9.49 ± 1.37

bpp = 6.89 ± 0.64

O. EvdokimovC. Pinkenburg

Jet-hadron correlations

Javier Castillo Heavy Ions Meeting – Irfu/SPhN – 17/9/2010

1.0<pTassoc<2.5 GeV/c

0-20% Au+Au pp

STAR Preliminary

STAR Preliminary

STAR Preliminary

Au+Au vs. pp: Softer momentum distribution for recoil hadrons Significant away-side broadening

flat BG subtraction

26

We see significant Jetsuppression in CuCu

Jet RAA is comparable to 0 RAA

O. EvdokimovC. Pinkenburg

Conclusion

• RHIC– Extensive and detailed studies are being performed

• LHC– First results are coming fast

Heavy Ions Meeting – Irfu/SPhN – 17/9/2010 27Javier Castillo