# Presentation: 560514

## LMVM RBUB numbers (HW update)

- R. Seto
- Light-Heavy PWG
- July 6, 2006

## Outline

- HW
- Lum (not finalized)
- Most data sets will be DAQ limited (5kHz)
- NOT true for low energy (63 GeV) AuAu
- Propose to run 63 GeV Iodine on Iodine (A=127) to increase rate; we will then be DAQ limited for 63 GeV Iodine on Iodine
- Eg. Run 7: AuAu 200, Run 8: 63 GeV Iodine, Run 9: something else(dAu...) or some permutation
- Some assumptions
- 63 GeV 10% of 200 GeV
- Iodine is 10x Au
-  production scales with Nch

## Rho assumptions

-  rate = 2x 
-  bkg integration = 600 MeV

- NA60

- NA60

## HW

- Use Kozlov post-QM numbers shown at the pwg last week
- 1030M min bias
- 1740 , S/B=1/76
- Some volunteer should go through last year's BUP and this year's CAD guidance and formulate the prescription for the assumed evts recorded that all people should be using in formulating their contributions to this year's BUP.
- Eff~0.36=0.6(RHIC)*0.6(PHENIX)
- Min Bias recorded ~ 5kHz
- Use CAD delivered Lum/week
- 0.290 nb-1/wk for 200 GeV AuAu

## Luminosity

- Assumptions:
- DAQ 5 KHz recorded
- RHIC Z vertex = 20 cm, 80% in central peak
- Eff for phenix =0.6
- Eff for RHIC 0.6
- For 200 GeV AuAu
- L/week=0.290 nb-1
- L(avg)=8E26  L(max)=3.6E27
- min bias rate
- avg= 5.0 kHz  (4.5-round up)
- max = 20. kHz
-  so limit to 5kHz

- 63 GeV AuAU
- L=10% of 200 GeV
- Min bias
- 0.5kHz (avg)
- 2.kHz (max)
- 63 GeV Iodine on Iodine
- L=13x AuAuGeV
- Min bias =5.8b
- 5kHz (avg) (4.8-round up)
- 20.kHz (max)
- so limit to 5kHz

## Events

- DAQ limited
- 5kHz*6Msecs(10 weeks) *0.6(phenix eff)*0.6(RHIC eff)= 1.1E10 events
- Rate limited, e.g. AuAu at 63
- L/week*bbcz *10 weeks *  *PHENIX eff=
- .029 nb-1/week*0.8*10weeks*7b*0.6=9.7E8 ~1B events

## Run 4  200 GeV AuAu  

- Ozawa et al
- 700M evts
- Counted events 30 MeV=60 MeV
- 
- Saw 644 330
- S/B=644/100K
- 
- Saw 748 200
- S./B=750/40K

- Kozlov et al
- 1740M events
- Counted events 0.997 to 1.041=44 MeV
- 
- Saw 1740
- S./B=1/76=1740/132K
- Kozlov should have seen
- 1502 
- Background 196K
- (see spares for calculation)

## Scaling signal and background

- Scale signal with dN/dy
- Scale background with (dN/dy)2
- AuAu min bias Np=109
- 200 GeV dN/dy=332
- 63 GeV dN/dy=223
- II min bias Np=94 (guess)
- 63 GeV II dN/dy=188
- HBD
- Signal eff 0.4
- S/B in central AuAu improves by factor 100
- Signal suppressed by 0.4
- background  suppressed by .004
- .06 for background electrons

- From Milov Analysis note

## Numbers

- HBD A – HBD as in CDR
- HBD B – HBD 4x poorer in rejecting bkg, i.e. 2x worse per electron

- For RHO: Good measurement at 200 GeV AuAu, 63 GeV Iodine
- i.e. ~ 5K events can be broken up into bins of pt and centrality and still
- Give a reasonable signal

- Iodine at 63 will give connection to NA 60 result.

## Spares

## Slide 11

## Slide 12

## Between Ozawa and Kozlov new phi and omega– just use the ratio signal/signal, bkg/bkg

- Kozlov new has a different “looser” cut for electrons – which means
- He keeps more electrons in the case of both signal and background
- He also introduces more π’s for bkg
- Signal
- Let a=eff old, b=eff new (a<b) and X is the total number of events with ’s (or equivalently the number of ’s total
- a2X=748      b2X=1740
- So in the case of the ,X is different (call it  X’), but the old to new ratio of ’s is just a2/b2 or the ratio of old to new ’s
- Bkg
- Let M=# ee pairs per event N=M=#ππ pairs, c,d be prob that π is misidentified as an electron in the “old” and “new” schemes respectively
- Bkg (M+ M)2= (1+ )2M2 if you take everything
- Bkg old (aM+cN)2~ (a+ c)2M2 ~40K
- Bkg new (bM+dN)2~ (b+ d)2M2 ~1320K
- In the case of the  we have a new M and N, i.e. M’ and N’
- N=M   N’= ’M’
- BIG Assumption? = ’
- Then in you work out the algebra you can just use the ratios i.e.

## phi production (ppg016)

- I assume phi production proportional to dNch/dy at energies greater than 60

- 63

- 200

## Slide 15

## Slide 16

## Luminosity at lower energy

- Full energy

- 63 GeV

## HW

- Increase in lum going to lower A is balanced by Ncoll to factor of 2
- Find ncoll, npart for lighter species
- Milov/workarea/tmp
- Ask Roser et al for RHIC lums at lower energy, lighter species, specifically 62 GeV AuAu, II, CuCu, SiSi, dAu, pp