1 Logo et image Alice Christophe Suireipno in

2 Infos • 31 pays, 111 instituts, ~ 1000 collaborateurs • Membres du groupe

3 p+p @ √snn = 0. 9 Te. V Accepted by EPJC for publication

4 Le spectrometre a muon • gs Christophe. Suire@ipno. in 2 p 3. fr

5 Collision p+p @ √snn = 900 Ge. V p+p @ √snn=900 Ge. V,

6 Historique • 2007 : installation et intégration – Décembre 2007 : premier “cosmic

7 LHC first beams and collisions Christophe. Suire@ipno. in 2 p 3. fr

8 Historique • Decembre 2009 : la premiere trace d’un muon dans un collision

9 Number of events • ALICE : – 435890 good events at √snn =

10 p+p @ √snn = 0. 9 Te. V ALICE first paper • November

11 p+p @ √snn = 0. 9 Te. V ALICE first paper Accepted by

12 Les premiers muons 9 runs selected (taken during 11 -12 Dec. 2009). Christophe.

13 J/ψ in p+p at √snn = 900 Ge. V 3 di-muons candidates seen

14 “Demain”, p+p @√snn = 7 Te. V Quelques dizaines (centaines ? ) de

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1 Logo et image Alice Christophe. Suire@ipno. in 2 p 3. fr

2 Infos • 31 pays, 111 instituts, ~ 1000 collaborateurs • Membres du groupe ALICE IPNO – – – – – Bruno Espagnon (MC resp) Yves Le Bornec (DR) Cynthia Hajidakis (CR) Christophe Suire (CR) Bruno Boyer (These) Mercedes Lopez-Noriega (Post-doc) Daniel Tapia Takaki (Post-doc) Louis Bimbot (DR 50%) Nicole Willis (jeune retraitee) Marie-Pierre Comets (detachement ASN) Christophe. Suire@ipno. in 2 p 3. fr

3 p+p @ √snn = 0. 9 Te. V Accepted by EPJC for publication on 1 Dec. 2009 Le 23 novembre 20009 : 43 minutes de collisions, 234 bons evenements enregistres Nombre moyen de particules chargees a rapidite centrale : d. N/dh = 3. 10 ± 0. 13 (stat) ± 0. 22 (syst) A partir du 6 decembre, le LHC offre des “faisceaux stables, 435890 evenements collectes a √snn = 0. 9 Te. V (tout ALICE) et des faisceaux “quiet” ~60000 evenements a √snn = 2. 36 Te. V (tracker silicium) last time measured at the ISR for pp Christophe. Suire@ipno. in 2 p 3. fr

4 Le spectrometre a muon • gs Christophe. Suire@ipno. in 2 p 3. fr Distribution en moment tranverse des muons reconstruits sur un echantillon de 200 000 evenements « min-bias » : les premières comparaison données-simulations donnent un accord remarquable (sans « finetuning » ) !

5 Collision p+p @ √snn = 900 Ge. V p+p @ √snn=900 Ge. V, les premiers di-muons sont observes Christophe. Suire@ipno. in 2 p 3. fr

6 Historique • 2007 : installation et intégration – Décembre 2007 : premier “cosmic run Full Alice” avec la station 1 (Orsay) du spectromètre a muons. • 2008 : installation et intégration continuent – Deux “cosmic run Full Alice” – Incident LHC Le premier cluster • 2009 : intégration continue, plus de tests… – Un muon “ cosmic run” (03/09) – “cosmic run Full Alice” – 23 Novembre 2009 : Les premières collisions p+p at √snn = 900 Ge. V Christophe. Suire@ipno. in 2 p 3. fr

7 LHC first beams and collisions Christophe. Suire@ipno. in 2 p 3. fr

8 Historique • Decembre 2009 : la premiere trace d’un muon dans un collision p+p observee dans le spectrometre Christophe. Suire@ipno. in 2 p 3. fr

9 Number of events • ALICE : – 435890 good events at √snn = 0. 9 Te. V with all detectors – ~60000 events at √snn = 2. 36 Te. V with ITS only • ATLAS : – ~540000 events at √snn = 0. 9 Te. V with all detectors (especially the Sitracker) – ~ 34000 events at √snn = 2. 36 Te. V (Si-tracker not always ? ) • CMS : – number of events extracted from luminosity (30% error) – but 10 (0. 4) µb-1 @√snn = 0. 9 Te. V (2. 36) 400000 (16000) events • LHCb – 342360 good events at √snn = 0. 9 Te. V with all detectors – ~ 30000 events at √snn = 2. 36 Te. V (no Si-Tracker/Ve. Lo) Christophe. Suire@ipno. in 2 p 3. fr

10 p+p @ √snn = 0. 9 Te. V ALICE first paper • November 23 rd, around 16 h 40, the first pp collision appeared on the online display (ALIEVE) a) 284 good events recorded in 43 minutes b) Only ITS, 6 layers of silicon pixel, drift and strip detectors, is powered on. NB : ALICE is the only LHC experiment that switched on its internal tracker for the very first collisions. LHC beams were declared quiet not stable ! c) No B field d) Goal was clearly to get the first LHC paper : dn/dη with SPD tracklets (i. e. tracks made of SPD hits only ) Christophe. Suire@ipno. in 2 p 3. fr

11 p+p @ √snn = 0. 9 Te. V ALICE first paper Accepted by EPJC for publication on 1 Dec. 2009 The average number of charged particles created perpendicular to the beam in pp collisions at 900 Ge. V is: d. N/dh = 3. 10 ± 0. 13 (stat) ± 0. 22 (syst) Pas assez de statistique pour la physique du spectrometre a muon 435890 good events at √snn = 0. 9 Te. V with all detectors ~60000 events at √snn = 2. 36 Te. V with ITS only Cependant …. last time measured at the ISR for pp Christophe. Suire@ipno. in 2 p 3. fr

12 Les premiers muons 9 runs selected (taken during 11 -12 Dec. 2009). Christophe. Suire@ipno. in 2 p 3. fr

13 J/ψ in p+p at √snn = 900 Ge. V 3 di-muons candidates seen in the Alice muon spectrometer… but Run 104852; Ev 650 Inter. and Muon trig minv = 0. 81 Ge. V/c 2 Run 104867; Ev 170 Inter. and Muon trig minv = 1. 8 Ge. V/c 2 Run 104892; Ev 650 Inter. and Muon trig minv = 0. 79 Ge. V/c 2 Quite understandable : ~ 20 µb-1 of p+p @ √snn = 900 Ge. V If : σJ/ψ ~ 1 µb, BR J/ψ µ-µ+ =6% , Acc. x Eff. spectro ~ 0. 1 x 0. 9 Expected nof of J/ψ = 0. 1 Let’s try in 2010 ! Christophe. Suire@ipno. in 2 p 3. fr

14 “Demain”, p+p @√snn = 7 Te. V Quelques dizaines (centaines ? ) de pb-1 en collisions p+p Physique QCD, statistique a peine suffisante pour la physique electro-faible Et surtout quelques centaines de millions de collisions Pb+Pb @√snn = 7 Te. V Christophe. Suire@ipno. in 2 p 3. fr