Luminosity estimation for  GLD conceptual design  by TT (05)

---

GLD-CAL calibration by muons : August/05
suppose the strip size is S=1 x 5 cm^2 (ECAL), 1 x 20 cm ^2 (HCAL)
and placed at R from IP (R=230cm for ECAL and 350cm for RCAL at 90 deg.)
acceptance dOmega=S/piR^2= 3 * 10^-5 (ECAL)
acceptance dOmega=S/piR^2= 5 * 10^-5 (HCAL)
assume spherical distribution of muon emission
N muons by luminocity=L x (time)=t , cross section of (ee-mumu)=cs
N=L t cs  dOmega
if N=10 events, L=10^33 cm^-2/s, and cs =3nb=3*10^-33 cm^2,
t=N/2L/cs / dOmega=10/3/2 / 3*10^-5 = 5*10^6 sec =60 days~2 months

for HCAL t(H)=2/(5/3)=1.2 months   for 10 events (minimum number of events)

---

---