1. Chic @ SPS (Charm in Heavy Ion Collisions) Detector design A 3 rd generation experiment to study charm with proton and ion beams on fixed target at SPS 1Frédéric Fleuret - LLR

2. Physics motivations – 2 key questions 1.Measure  c in A+A Understanding similar J/  suppression observed at SPS and RHIC: 1.Either more suppression at RHIC compensated by recombination 2.Or J/  suppression due to  c only  sequential suppression How  c is suppressed relative to J/  ? What is the dependence with y, p T, N part,… ? Mandatory to draw the whole picture (SPS.vs. RHIC.vs. LHC) 2.Measure charmonia production in p+A what is the depence of charmonia suppression with rapidity ? Crucial to understand effects due to cold nuclear matter Frédéric Fleuret - LLR2

3. 1. Measure  c in A+A Frédéric Fleuret - LLR3 Eur. Phys. J. C49 (2007) 559 N J/  ~ 60% direct + ~30% from  c + ~10% from  ’ Phys. Rev. Lett. 99, 132302 (2007)  c Suppression ? Direct J/  Suppression ? Benchmark: measure  c in PbPb at mid-rapidity NA50NA60 ’’  c ?? Direct J/ 

4. 2. Measure charmonia in p+A Frédéric Fleuret - LLR4 Euro. Phys. J. C48 (2006) 329. J/  and  ’ suppression in p+A collisions as a function of L  Measuring different charmonium states gives key information on nuclear « absorption » and production mechanism. J/  rapidity distribution in p+A collisions (asymetry wrt y cm =0)  Measuring charmonium in a wide x F range is important to identify possible (anti)shadowing effects NA50 ’’ J/ 

5. 2. Measure charmonia in p+A Frédéric Fleuret - LLR5 Possible to access large x F if measuring charmonia at rapidity up to y*~2 With M=3.1 and  s=17.2 GeV (158 GeV) x F = 1  y* = 1.7 With M=3.1 and  s=29.1 GeV (450 GeV) x F = 1  y* = 2.2 Y*=2  x F = 0.8 E866, Phys. Rev. Lett. 84, 3256-3260 (2000)  Measuring charmonium in a wide x F range is important to identify possible (anti)shadowing effects

6. Experimental landscape Current landscape – Fixed target : SPS/CERN NA38/50/60 experiments –  s NN = 17 – 30 GeV Statistics :100 000’s J/  Data sets : p+A w/ A=p, d, Be, Al, Cu, Ag, W, Pb; S+U, In+In, Pb+Pb Small rapidity coverage (typically y  [0,1]) – Collider : RHIC/BNL Phenix, Star experiments –  s NN = 200 GeV Statistics : 1000’s J/  (10000’s since 2007) Data sets : p+p, d+Au, Cu+Cu, Au+Au Large rapidity coverage (y  [-0.5,0.5], y  [-2.2,-1.2] and y  [1.2,2.2]) – Collider : LHC/CERN Alice, CMS, Atlas experiments (  s NN = 5,5 TeV) Statistics : 100000’s J/  Data sets : p+p, Pb+Pb, p+Pb Large rapidity coverage (|y|<2.5 ATLAS/CMS, |y|<0.9 and -4.0 < y < -2.5 ALICE) Feedback : 4 key points 1.High statistics  draw clear suppression pattern in Hot Nuclear Matter and Cold Nuclear Matter 2.Large data set  draw clear suppression pattern in Cold Nuclear Matter 3.Large x F (rapidity) coverage  understand suppression mechanism in Cold Nuclear Matter 4.As large sample of quarkonium states as possible  understand suppression mechanism in Hot Nuclear Matter and Cold Nuclear Matter Frédéric Fleuret - LLR6

7. Expected yield Need high intensity p and Pb beams (~ 10 7 Pb/sec) NA50/NA60 beam line not available (NA62) H2 beam line occupied by NA61 H4 and H8 available but need shielding for HI NA50: European Physical Journal C39 (2005) 335 New measurement of J/  suppression in Pb+Pb at 158 GeV/nucleon 35 days of data taking in 2000 ~1.10 7 Pb/s over 5s bursts every 20s 4 mm thick Pb target (10% I ) ~ 100 000 J/    +  - within y*  [0,1] (on tape) Expect fair amount of  c : N J/  ~ 60% direct + ~30% from  c + ~10% from  ’ With same conditions as 2000 NA50 setup  ~30 000  c expected (asuming same acceptance) Expect more with larger y* range Expect more with thicker target (1cm for instance) Frédéric Fleuret - LLR7 North Area Beamlines

8. Fixed target experiments Frédéric Fleuret - LLR8 Active Target  absorber  spectrometer  muID Active target, but no vertex for open charm and not very good mass resolution

9. Fixed target experiments Frédéric Fleuret - LLR9 Active Target  telescope  absorber  spectrometer  muID + NA50 See NA50 Active target, vertex for open charm and not very good mass resolution

10. CHIC: 3 rd generation Active target  vertex  spectrometer  calorimeter  absorber  muID CHIC: 3 rd generation Active target  vertex  spectrometer  calorimeter  absorber  muID Fixed target experiments Frédéric Fleuret - LLR10 Dipole field Muon Filter (absorber) target vertex tracking MuID Beam EMCal Active target, vertex for open charm, calorimeter for  c and very good mass resolution

11. Detector – tracking The NA60 example Pixel detector 16 planes – 96 chips total 32 x 256 pixels / chip Pixel size = 425 × 50  m² Magnetic field = 2.5 T × 40 cm Pixel detector 16 planes – 96 chips total 32 x 256 pixels / chip Pixel size = 425 × 50  m² Magnetic field = 2.5 T × 40 cm Momentum resolution @J/  mass (typical p  ~ 15 GeV/c) (R. S. priv. Comm.) 11Frédéric Fleuret - LLR

12. Detector – tracking NA60 pixel momentum resolution (R.S. priv. Comm.) (Particle Data Group, NIMA 410, 284-292 (1998))  = curvature B = magnetic field  = measurement error N = number of points measured L = projected length of the track onto the bending plane  Major parameters for improvement :  Magnetic field and measurement error (linearly)  Length into magnetic field (quadratically)  Major parameters for improvement :  Magnetic field and measurement error (linearly)  Length into magnetic field (quadratically) ~40 cm B (T)L (cm)  (imp.)  P/P (%)  M (MeV) 2.540×1~ 6~130 2.560×1~ 2.7~60 2.580×1~ 1.5~30 2.5100×1~1~20 NA60  L B =40 cm  L B =100 cm   P/P ~1%   M J/  ~ 20 MeV 12Frédéric Fleuret - LLR Magnetic field Magnet length

13. Detector – tracking Size, position, resolution : tentative design – toy example B (T)L (cm)  P/P (%)  M (MeV) 2.540~ 6~120 2.560~ 2.7~60 2.580~ 1.5~30 2.5100~1~20  NA60 13Frédéric Fleuret - LLR 6 plane vertex @ r min = 0.5 cm  z min (  *=0.5)~7.5 cm 6 planes from z=8 cm to z=18 cm 6 plane vertex @ r min = 0.5 cm  z min (  *=0.5)~7.5 cm 6 planes from z=8 cm to z=18 cm  =-0.5  =0.5  =1 11 plane spectrometer @ z max = 120 cm  r max (  *=-0.5)~22 cm 11 planes from z=20 cm to z = 120 cm 11 plane spectrometer @ z max = 120 cm  r max (  *=-0.5)~22 cm 11 planes from z=20 cm to z = 120 cm  =-0.5  =0.5  CHIC 22 7.5 Track particles within  *  [-0.5 ; 1]

14. Detector – tracking Size, position, resolution : tentative design – toy example B (T)L (cm)  P/P (%)  M (MeV) 2.540~ 6~120 2.560~ 2.7~60 2.580~ 1.5~30 2.5100~1~20  NA60 14Frédéric Fleuret - LLR 6 plane vertex @ r min = 0.5 cm  z min (  *=0.5)~7.5 cm 6 planes from z=8 cm to z=18 cm 6 plane vertex @ r min = 0.5 cm  z min (  *=0.5)~7.5 cm 6 planes from z=8 cm to z=18 cm  =-0.5  =0.5  CHIC 7.5 Track particles within  *  [0.5 ; 2] 11 plane spectrometer @ z max = 120 cm  r max (  *=-0.5)~22 cm 11 planes from z=100 cm to z = 200 cm 11 plane spectrometer @ z max = 120 cm  r max (  *=-0.5)~22 cm 11 planes from z=100 cm to z = 200 cm  =0.5  =2 22

15. Detector – tentative design Frédéric Fleuret - LLR15 20 cm 40 cm 60 cm 80 cm 100 cm 120 cm 1 m3 m4 m5 m6 m2 m Vertex detector : R min = 0.5 cm Z min = 7.5 cm R max = 3.5 cm Z max = 18 cm Spectrometer : R min = 1 cm Z min = 20 (100) cm R max = 22 cm Z max = 120 (200) cm

16. Goal : measure the photon from  c  J/  +  Issues 1.Low energy photon (similar to  0   ) 2.High multiplicity of photon from  0 /    3.High multiplicity of charged particles (  +/- ) Detector – calorimetry 16Frédéric Fleuret - LLR ~500 MeV ~3 GeV Pythia 6.421 - p+p -  s = 17.2 GeV

17. Goal : measure the photon from  c  J/  +  Issues 1.Low energy photon (similar to  0   ) 2.High multiplicity of photon from  0 /    3.High multiplicity of charged particles (  +/- ) Detector – calorimetry 17Frédéric Fleuret - LLR WA98: Phys. Lett. B458: 422-430, 1999) Phobos: Phys. Rev. C74, 021901, 2006 ~500  ~340  ~350  +/- Epos 1.6 : Pb+Pb @ 17.2 GeV ~400  ~370  +/- 0 – 5% 0 – 5% Pb+Pb most central  ~500  + 400  +/- (we don’t need to go that central for  c ) 0 – 5% Pb+Pb most central  ~500  + 400  +/- (we don’t need to go that central for  c ) Epos 1.6 : Pb+Pb @ 17.2 GeV

18. Need very high segmentation – to separate two electromagnetic showers – To isolate photons from  +/- contamination W + Si calorimeter à la Calice – 30 layers – 0.5 x 0.5 cm 2 pads – 24 X 0 in 20 cm W+Si : two relevant quantities Detector – calorimetry 18Frédéric Fleuret - LLR 1 st relevant quantity : distance between two incoming particles  Min. distance between 2 particles at impact = 1 free pad = 1 cm (for 0.5×0.5 cm²)  distance between two incoming particles must be > 1 cm  N photons  N/2 neutrals (  0 +  )  N  +/-  N  + N  +/- = 2N particles  distance between two photons must be > 2 cm (1cm×2N/N) 1 st relevant quantity : distance between two incoming particles  Min. distance between 2 particles at impact = 1 free pad = 1 cm (for 0.5×0.5 cm²)  distance between two incoming particles must be > 1 cm  N photons  N/2 neutrals (  0 +  )  N  +/-  N  + N  +/- = 2N particles  distance between two photons must be > 2 cm (1cm×2N/N) badgood 2 nd relevant quantity : EM shower transverse size  Moliere Radius R M : 90% of the shower energy  Distance between two photons must be > 2 cm (2 R M ) 2 nd relevant quantity : EM shower transverse size  Moliere Radius R M : 90% of the shower energy  Distance between two photons must be > 2 cm (2 R M ) Geometrical condition: in principle  > 2cm

19. Detector – calorimetry Size and position : tentative design  >4  2  1  >2 [-0.5:0.5] r min r max Z 20 cm 19Frédéric Fleuret - LLR 0 – 5% most central Pb+Pb events as measured by WA98 Distance between two photons Closer position to the target w/  >2cm:  Z = 205 cm [-0.5:0.5]  R min = 13.6 cm  R max = 40.9 cm Using 0.5 x 0.5 cm² pads Closer position to the target w/  >2cm:  Z = 205 cm [-0.5:0.5]  R min = 13.6 cm  R max = 40.9 cm Using 0.5 x 0.5 cm² pads

20. Detector – calorimetry Size and position : alternative design r min r max Z 20 cm 20Frédéric Fleuret - LLR Warning : not clear that  >2 cm is large enough; for instance, R M (W+Si) > R M (W). Try alternative design: taking  >4cm with z = 205 cm, R min =30 cm, R max = 55cm   *  [-0.8, -0.3]  loose some  c acceptance, but safe !!! Must check with full simulation what is optimum  ! Warning : not clear that  >2 cm is large enough; for instance, R M (W+Si) > R M (W). Try alternative design: taking  >4cm with z = 205 cm, R min =30 cm, R max = 55cm   *  [-0.8, -0.3]  loose some  c acceptance, but safe !!! Must check with full simulation what is optimum  !  >4  >2  2

21. Detector – tentative design Frédéric Fleuret - LLR21 20 cm 40 cm 60 cm 80 cm 100 cm 120 cm 1 m3 m4 m5 m6 m2 m Vertex detector : Rmin = 0.5 cm Zmin = 7.5 cm Rmax = 3.5 cm Zmax = 18 cm Spectrometer : Rmin = 1 cm Zmin = 20 (100) cm Rmax = 22 cm Zmax = 120 (200) cm Calorimeter  >2 cm: acceptance 1 Rmin = 14 cm Zmin = 205 cm Rmax = 41 cm Zmax = 225 cm Calorimeter  >4 cm: acceptance 2 Rmin = 30 cm Zmin = 205 cm Rmax = 55 cm Zmax = 225 cm   *  [-0.5, 0.5]   *  [-0.8, -0.3]

22. Performances in p+p Pythia 6.421 – p+p –  s = 17.2 GeV – 20 000 generated events Include  P/P=1% Include  E/E=20%/  E Frédéric Fleuret - LLR22 PYTHIA 6.421 20000 events Y*=0  Y CMS ~2.92 A J/  ~18.4% A  ~8.5% Acceptance 1 2  from J/  in -0.5<y*<0.5 1  from  c in -0.5<y*<0.5 A  ~3.2% A J/  ~18.4% Acceptance 2 2  from J/  in -0.5<y*<0.5 1  from  c in -0.8<y*<-0.3

23. Performances in p+p – acceptance 1 Pythia 6.421 – p+p –  s = 17.2 GeV : 20 000 generated events Frédéric Fleuret - LLR23 2  from J/  within -0.5<y*<0.5 1  from  c within -0.5<y*<0.5 2  from J/  within -0.5<y*<0.5 1  from  c within -0.5<y*<0.5

24. Performances in p+p – acceptance 2 Pythia 6.421 – p+p –  s = 17.2 GeV : 20 000 generated events Frédéric Fleuret - LLR24 2  from J/  within -0.5<y*<0.5 1  from  c within -0.8<y*<-0.3 2  from J/  within -0.5<y*<0.5 1  from  c within -0.8<y*<-0.3

25. Standard designAlternative design Frédéric Fleuret - LLR25 Performances in p+p -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 J/  cc cc

26.  ++ DHCal http://newsline.linearcollider.org/archive/2010/20101104.html Detector – absorber Absorber type 26Frédéric Fleuret - LLR NA50/NA60 : measure muon momentum after the absorber  must minimize multiple scattering – Must use low Z material: best = BeO (but expensive) – NA50 : 0.6 m BeO + 4 m C + 0.6 m Fe = 5.2 m CHIC : measure muon momentum before the absorber  minimization of multiple scattering less crucial  can use Fe material To absorb  +/- Need to match muon track position between spectrometer and trigger : Use an instrumented Fe absorber Can match muon track momentum between spectrometer and trigger : Use magnetized Fe absorber ? Minos

27. Detector – absorber Pion absorption and muon energy loss 27Frédéric Fleuret - LLR At least 2 m Fe length needed Fraction of hadron energy absorbed in Fe Fraction of hadron energy absorbed in Fe All  +/- stopped with a ~2.0 m Fe absorber

28. Detector – absorber Pion absorption and muon energy loss 28Frédéric Fleuret - LLR dE/dx ~ 2 MeV g -1 cm 2 Fe density ~ 7.8 g cm -3 dE/dx ~ 15.6 MeV cm -1 Muon energy loss in Fe Muon energy loss in Fe All  +/- stopped with a 2.0 m Fe absorber but need more Fe to stop muons from pion decay  2.0 m Fe   E/  x ~ 15.6 x 200 ~ 3.1 GeV  A J/  ~ 18.4 %  3.2 m Fe   E/  x ~ 15.6 x 320 ~ 5 GeV  A J/  ~ 18.0 %  3.8 m Fe   E/  x ~ 15.6 x 380 ~ 6 GeV  A J/  ~ 17.3 %  4.5 m Fe   E/  x ~ 15.6 x 450 ~ 7 GeV  A J/  ~ 16.1 % All  +/- stopped with a 2.0 m Fe absorber but need more Fe to stop muons from pion decay  2.0 m Fe   E/  x ~ 15.6 x 200 ~ 3.1 GeV  A J/  ~ 18.4 %  3.2 m Fe   E/  x ~ 15.6 x 320 ~ 5 GeV  A J/  ~ 18.0 %  3.8 m Fe   E/  x ~ 15.6 x 380 ~ 6 GeV  A J/  ~ 17.3 %  4.5 m Fe   E/  x ~ 15.6 x 450 ~ 7 GeV  A J/  ~ 16.1 % 3 5 7

29. Pb Beam intensity – NA50  5.10 7 ions/bunch  10 7 ions/sec (with a bunch time length ~ 5 sec) – Luminosity : L = N b x N T = N b x (  x e x N A )/A = 10 7 x(11.35 x 1 x 6.02 10 23 )/207.19 = 0.3  b -1 s -1 Number of min bias events (for Pb+Pb) –  I =68.8 x (A 1/3 proj + B 1/3 targ – 1.32) 2   PbPb minbias =68.8 x (208 1/3 + 207.19 1/3 – 1.32) 2 =7.62 barn – Nevents/sec ~ 0.3 10 6 x 7.62 ~ 2.3 MHz Event rejection : Detector – trigger rate in Pb+Pb Frédéric Fleuret - LLR29 10 000 Pb+Pb minbias events generated with EPOS 1.6 At least 2  in the Detector (44 events) 3.2m Fe abs.: P z >5 GeV/c: Trigger accepts 44/10000 events  N events /sec ~ 2.3 MHz x 4.4 10 -3 ~ 10 kHz 3.8m Fe abs.: P z >6 GeV/c: Trigger accepts 12/10000 events  N events /sec ~ 2.3 MHz x 1.2 10 -3 ~ 2.8 kHz 4.5m Fe abs.: P z >7 GeV/c: Trigger accepts 3/10000 events  N events /sec ~ 2.3 MHz x 3 10 -4 ~ 700 Hz 3.2m Fe abs.: P z >5 GeV/c: Trigger accepts 44/10000 events  N events /sec ~ 2.3 MHz x 4.4 10 -3 ~ 10 kHz 3.8m Fe abs.: P z >6 GeV/c: Trigger accepts 12/10000 events  N events /sec ~ 2.3 MHz x 1.2 10 -3 ~ 2.8 kHz 4.5m Fe abs.: P z >7 GeV/c: Trigger accepts 3/10000 events  N events /sec ~ 2.3 MHz x 3 10 -4 ~ 700 Hz At least 2  in the Detector (12 events) At least 2  in the Detector (3 events) At least 2  in the Detector (329 events) Absorber starts @ 205 cm  +/- stop decaying after 1 I in tungsten ( I ~10cm)   +/- stop decaying @ 2.15 m Absorber starts @ 205 cm  +/- stop decaying after 1 I in tungsten ( I ~10cm)   +/- stop decaying @ 2.15 m

30. Detector – tentative design Frédéric Fleuret - LLR30 20 cm 40 cm 60 cm 80 cm 100 cm 120 cm 1 m3 m4 m5 m6 m2 m Vertex detector : Rmin = 0.5 cm Zmin = 7.5 cm Rmax = 3.5 cm Zmax = 18 cm Spectrometer : Rmin = 1 cm Zmin = 20 (100) cm Rmax = 22 cm Zmax = 120 (200) cm Calorimeter  >2 cm: acceptance 1 Rmin = 14 cm Zmin = 205 cm Rmax = 41 cm Zmax = 225 cm Calorimeter  >4 cm: acceptance 2 Rmin = 30 cm Zmin = 205 cm Rmax = 55 cm Zmax = 225 cm   *  [-0.5, 0.5]   *  [-0.8, -0.3] 1 m3 m4 m5 m6 m2 m 2.5 cm 7.5 cm

31. Performances Test performances with tentative design – Detector design: test two setups 1.Standard design : -0.5 7 GeV | z vertex (  )<215cm| -0.5<y*(  )<0.5 2.Alternative design : -0.5 7 GeV | z vertex (  )<215cm| -0.8<y*(  )<-0.3 Trig events w/ 2 muons from J/  within acceptance – Event sample : p+p @  s = 17.2 GeV 20 000  c2 events generated with Pythia 6.421 Muon momentum smeared with  P/P=1% Photon energy smeared with  E/E=20%/  E – Event sample : Pb+Pb @  s = 17.2 GeV 10 000 minBias events generated with Epos 1.6 1 pythia  c2 (2  + 1  ) embedded in each Pb+Pb event Muon momentum smeared with  P/P=1% Photon energy smeared with  E/E = 20%/  E Test performances with tentative design – Detector design: test two setups 1.Standard design : -0.5 7 GeV | z vertex (  )<215cm| -0.5<y*(  )<0.5 2.Alternative design : -0.5 7 GeV | z vertex (  )<215cm| -0.8<y*(  )<-0.3 Trig events w/ 2 muons from J/  within acceptance – Event sample : p+p @  s = 17.2 GeV 20 000  c2 events generated with Pythia 6.421 Muon momentum smeared with  P/P=1% Photon energy smeared with  E/E=20%/  E – Event sample : Pb+Pb @  s = 17.2 GeV 10 000 minBias events generated with Epos 1.6 1 pythia  c2 (2  + 1  ) embedded in each Pb+Pb event Muon momentum smeared with  P/P=1% Photon energy smeared with  E/E = 20%/  E Frédéric Fleuret - LLR31

32. Standard designAlternative design Frédéric Fleuret - LLR32 Performances in p+p -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~no Bkg S/B(  c )~1.2 -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~no Bkg S/B(  c )~1.2 -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~no Bkg S/B(  c )~0.9 -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~no Bkg S/B(  c )~0.9

33. Standard designAlternative design Frédéric Fleuret - LLR33 Improve p+p S/B Apply a cut on M  : Reject all photon pairs belonging to M   [100 MeV, 160 MeV] (M  0 = 135 MeV) Apply a cut on M  : Reject all photon pairs belonging to M   [100 MeV, 160 MeV] (M  0 = 135 MeV) M  M  (  0 ) M  (1  from  c ) S/B(J/  )~no Bkg S/B(  c )~1.2 S/B(J/  )~no Bkg S/B(  c )~2.8

34. With no cut: S/B > 1 for standard design S/B > 0.5 for alternative design With M  cut: S/B ~ 3 for standard design S/B > 1 for alternative design No problem to measure  c in p+p. Shouldn’t be a problem in p+A With no cut: S/B > 1 for standard design S/B > 0.5 for alternative design With M  cut: S/B ~ 3 for standard design S/B > 1 for alternative design No problem to measure  c in p+p. Shouldn’t be a problem in p+A Performances in p+p – conclusion Frédéric Fleuret - LLR34 3229 events/20000 1170  c Standard design S/B~2.8 3229 events/20000 429  c Alternative design S/B~1.2

35. Standard designAlternative design Frédéric Fleuret - LLR35 Performances in Pb+Pb minBias -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~0.035 -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~0.035 -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~0.024 -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 P z (  ) > 7 GeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~0.024

36. Standard designAlternative design Frédéric Fleuret - LLR36 Performances in Pb+Pb minBias -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 P z (  ) > 7 GeV 100 < M  < 160 MeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~1.7 -0.5< y*(  )<0.5 -0.5<y*(  )<0.5 P z (  ) > 7 GeV 100 < M  < 160 MeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~1.7 -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 P z (  ) > 7 GeV 100 < M  < 160 MeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~0.44 -0.5< y*(  )<0.5 -0.8<y*(  )<-0.3 P z (  ) > 7 GeV 100 < M  < 160 MeV z vertex (  )<215 cm S/B(J/  )~11 S/B(  c )~0.44

37. Standard designAlternative design Frédéric Fleuret - LLR37 Improve S/B in Pb+Pb S/B(J/  )~11 S/B(  c )~3.6 J/    Opposite hemisphere Same hemisphere Apply a cut on cos  Reject all photons with cos  <0 Apply a cut on cos  Reject all photons with cos  <0 cos    S/B(J/  )~11 S/B(  c )~0.9 J/    Opposite hemisphere Same hemisphere cos   

38. In Pb+Pb minBias: – With no cut : S/B ~ 0.01 for both design – With M  cut and angular cut : S/B ~ 3.6 (0.9) for standard (alternative) design Measuring  c photons in -0.5 < y* < 0.5 is the best solution –  = 2 cm may be challenging, but we can reduce this constraint by: Finding a compromise between -0.5 < y* < 0.5 and -0.8 < y* < -0.3 Shifting the detector to a larger z – Note that  =2cm correspond to y*=0.5 for 0 – 5% most central Pb+Pb. In Pb+Pb minBias: – With no cut : S/B ~ 0.01 for both design – With M  cut and angular cut : S/B ~ 3.6 (0.9) for standard (alternative) design Measuring  c photons in -0.5 < y* < 0.5 is the best solution –  = 2 cm may be challenging, but we can reduce this constraint by: Finding a compromise between -0.5 < y* < 0.5 and -0.8 < y* < -0.3 Shifting the detector to a larger z – Note that  =2cm correspond to y*=0.5 for 0 – 5% most central Pb+Pb. Performances in Pb+Pb – conclusion Frédéric Fleuret - LLR38 1596 events/10000 107  c Standard design S/B~3.6 alternative design S/B~0.9 1596 events/10000 60  c

39. Conclusion Measuring  c, J/ ,  ’, open charm production in Pb+Pb needs : – Very good muon momentum resolution – High granularity calorimeter – Efficient trigger New technologies used to design a 3 rd generation detector – 2.5 T magnetic field along 1m – Si vertex detector, Si spectrometer – W+Si EMCal – Fe DHCal – Magnetized Fe absorber Results – J/  (  ’) measurement: Excellent performances expected –  c measurement: Good performance in p+p Good performance in Pb+Pb minBias  ok for peripheral and mid-peripheral Mid-central and central collisions collisions may be an issue. Need to perform more simulations to optimize the detector and analysis. Measuring  c, J/ ,  ’, open charm production in Pb+Pb needs : – Very good muon momentum resolution – High granularity calorimeter – Efficient trigger New technologies used to design a 3 rd generation detector – 2.5 T magnetic field along 1m – Si vertex detector, Si spectrometer – W+Si EMCal – Fe DHCal – Magnetized Fe absorber Results – J/  (  ’) measurement: Excellent performances expected –  c measurement: Good performance in p+p Good performance in Pb+Pb minBias  ok for peripheral and mid-peripheral Mid-central and central collisions collisions may be an issue. Need to perform more simulations to optimize the detector and analysis. Frédéric Fleuret - LLR39

40. backup Frédéric Fleuret - LLR40

41. Experimental challenges 4 key points 2.Large data set Draw clear suppression pattern in CNM Frédéric Fleuret - LLR41 NA50, Euro. Phys. J. C48 (2006) 329 Study P+Be, Al, Cu, Ag, W, Pb Using several targets is a key element to study quarkonia suppression in Cold Nuclear Matter At RHIC the study of CNM with d+Au suffered from the poor centrality resolution PHENIX, arXiv:1010.1246 R T =transverse radial position of the N-N collision relative to the center of the gold nucleus

42. Experimental challenges 4 key points 3.Large x F coverage in p+A Frédéric Fleuret - LLR42 Having a large xF coverage is a good point to study quarkonia suppression in Cold Nuclear Matter With M=3.1 and  s=17.2 GeV (158 GeV) x F = 1  y* = 1.7 With M=3.1 and  s=29.1 GeV (450 GeV) x F = 1  y* = 2.2 Y*=2  x F = 0.8 E866, Phys. Rev. Lett. 84, 3256-3260 (2000)

43. Experimental challenges 4 key points 3.Large sample of quarkonia states Frédéric Fleuret - LLR43 H. Satz, J. Phys. G 32 (2005) NA50, Eur. Phys. J. C49 (2007) 559 ’’ cc J/  N J/  ~ 60% direct + ~30% from  c + ~10% from  ’