Cosmic Rays in ALICE SPD TRIGGER – Analysis runs with B=ON – Some simulations ACORDE TRIGGER – New algorithm for cosmic muons – Analysis run with B=ON

SPD TRIGGER RUN : RUN without magnetic field Good tracking in TPC Lot of TPC clusters 141 tracks Iron interaction Mu Photonuclear intercation ???

SPD TRIGGER RUN : RUN without magnetic field Good tracking in TPC Lot of TPC clusters 707 tracks Iron interaction Mu Photonuclear intercation ???

Cosmic events with SPD trigger without magnetic field Analysis of high multiplicity events Run : – h 6m 9 events > 6 tracks – h 02m 3 events > 6 tracks – h 12m 210 events > 6 tracks and 20 events > 20 tracks SPD trigger  7-8 events per minute We can estimate at least 1 event per hour with high multiplicity  Probably muon intercation in iron

SPD TRIGGER with B=ON RUN night 8h 36min RUN evening 5h 25min RUN afternoon 4h 41min RUN evening 2h 53min RUN afternoon 2h 41min RUN evening 1h 06min – October 7/9 2008

SPD TRIGGER : high multiplicity events RUN – 7 events with Ntracks> (1) events interaction in iron 1 probable interaction in ITS 3 bad events RUN –3 events with Ntracks>18 2 bad events 1 no display

Mu interacting where ? RUN = Chunk = 90 Event = 868 Tracks = 19

Mu interacting in iron RUN = Chunk = 70 Event = 87 Tracks = 23

Mu interacting in iron RUN = Chunk = 180 Event = 4325 Tracks = 27

Previous event 4325 MUON P = 138 GeV MUON P = 183 GeV 27 tracks 9 particles 2 missing

Simulations of muon interaction in iron Muon in the range GeV Starting at Y=800 cm (above the magnet) Geant Fluka Only few event now (< 100)

High energy muon interacting in iron Muon - Pmu=930 GeV Yint=573 cm Mu  e+ e- Pe+=25 GeV Pe-=37 GeV

Previous event seen by TPC Interaction point

Previous event : TPC recostruction Tracks = 60 2 tracks for the primary muon: Pmu=396 GeV Pmu=306 GeV Instead of Pmu = 865 GeV ????

SPD TRIGGER with B=ON Few events with muon interactions in iron with respect the expectation with B=OFF Probably all events are e+ e- pair production created by muon with Emu > 500 GeV It should be necessary a long run with B=ON (1 day) with good data and reconstruction in TPC. Next step : Forced Geant or Fluka to create events with muon nuclear photoproduction interaction in iron Give an expectation of these events Give topology of these events for a possible TOF Trigger

ACORDE Trigger Analysis File:/Volumes/MRC/RunsA liEn/Run62107/ /AliESDs.root, N. of Event:8560, ACORDE Multiplicity:35, No. of ESD's tracks:148 How many muons we have ?

17 Float_t fCutMaxD=5; Float_t fCutMaxDz=40; Float_t fCutTheta=0.03; Float_t fCutMinDir=-0.99; Float_t kMaxD=1000; Double_t *p0 = tr0->GetParameter(); Double_t *p1 = tr1->GetParameter(); if (TMath::Abs(p0[3]+p1[3])>fCutTheta) return kFALSE; if (TMath::Abs(p0[1]-p1[1])>fCutMaxDz) return kFALSE; if (TMath::Abs(p0[0]+p1[0])>fCutMaxD) return kFALSE; Double_t d0[3], d1[3];tr0->GetDirection(d0); tr1->GetDirection(d1); if (d0[0]*d1[0] + d0[1]*d1[1] + d0[2]*d1[2] >fCutMinDir) return kFALSE; Float_t minDist=1000; // calculate distance Float_t dy = (tr0->GetY()+tr1->GetY()); Float_t sy2 = tr0->GetSigmaY2()+tr1->GetSigmaY2(); Float_t dphi = (tr0->GetAlpha()-tr1->GetAlpha()-TMath::Pi()); Float_t sphi2 = tr0->GetSigmaSnp2()+tr1->GetSigmaSnp2(); Float_t dtheta = (tr0->GetTgl()-tr1->GetTgl()); Float_t stheta2 = tr0->GetSigmaTgl2()+tr1->GetSigmaTgl2(); Float_t normDist = TMath::Sqrt(dy*dy/sy2+dphi*dphi/sphi2+dtheta*dtheta/stheta2); if (normDist>minDist) return kFALSE; return kTRUE; Bool_t IsPair(AliExternalTrackParam *tr0, AliExternalTrackParam *tr1) IsPair? Cuts defined by TPC people in TPC’s cosmic calibration Get the params of both tracks If both tracks are out of the cuts we don’t have a cosmic muon Get the direction of both tracks. If they are not in the same direction both belongs to some other kind of event Calculate the distance between both tracks. If it is bigger than 10 cms. Both tracks don’t belong to the same track If both tracks “pass” the previous filter then we have a COSMIC MUON TRACK !!!! Algorithm to match the tracks and get muons Mario Rodriguez

18 Number of Event: 18, Number of Tracks: 3, Number of Muons: 0 Delta Ray? Test on algorithm New Algorithm based on the classes : AliTPCcalibCosmic.cxx and AliESDCosmic.cxx by Marian Ivanov

19 Trigger: D0ASL, Number of Event: 1341, Number of Tracks: 2, Number of Muons: 1, Number of ACORDE fired Modules:1 Very beautiful Single Muon Event triggered by ACORDE

20 Trigger: D0LSR, Number of Event: 14855, Number of Tracks: 79, Number of Muons: 0, Number of ACORDE fired Modules:0 Also with another trigger we are counting very well !!!

21 Trigger: D0ASL, Number of Event: 716, Number of Tracks: 58, Number of Muons: 3, Number of ACORDE fired Modules:1 But, CAUTION, even though here we have an event from laser trigger of TPC calibration, the trigger cluster is from ACORDE!!!

N. TPC tracks vs ACORDE modules RUN 62107

RUN 62107, MAGNETIC FIELD ON Start Time: 09/10/ :03:37 End Time: 09/10/ :39:39 Duration: Days: 0 Hours: 8 Minutes: 36 Seconds: 2

Summary ACORDE New software to match tracks to get exact number of muons  under construction and test Study of the runs with B=ON –Muon Multiplicity, Energy distribution, Arrival Direction (Teta, Phi) Presentation at next Physics Forum Hardware  15 modules equipped with new photubes (in these days)