Contents of the Coincidence Ntuple

#
HBOOK name
corresp. FORTRAN variable
Note?
Description
1 helicity float(g_tslatch) beam helicity -- from hardware flag
2 EvTyp float(gen_event_type) Event Type
3 EvTime sngl(gevclock_fast) Event Time
4 beamx gSR_beamx beam position x = vetical down
5 beamy gSR_beamy beam position y = horizontal SOS side
6 hsxfp HSX_FP HMS Focal Plane x coord
7 hsyfp HSY_FP HMS Focal Plane y coord
8 hsxpfp HSXP_FP HMS Focal Plane x slope
9 hsypfp HSYP_FP HMS Focal Plane y slope
10 hsxtar HSX_TAR HMS recon target x -- vertical down
11 hsytar HSY_TAR HMS recon target y -- horizontal from HMS axis towards smaller angle
12 hsxptar HSXP_TAR HMS recon target x slope incl. offset hphi_offset!
13 hsyptar HSYP_TAR HMS recon target y slope incl. offset htheta_offset!
14 hszbeam HSZBEAM Lab Z coordinate of intersection of beam track with spectrometer ray, along beam downstream
15 hstheta hstheta electron scattering angle, lab system! based on momentum
16 w HINVMASS x Invariant Mass of remaing hadron system W = M + q
17 hsdelta HSDELTA HMS reconstructed relative momentum in % incl. offset
18 hmscorr HMScorrE x recoil Corrected electron energy based on momentum!
19 hcer_npe HCER_NPE_SUM Cerenkov signal amplitude == HMS Particle Id
20 hsshtrk HSTRACK_ET TOTAL SHOWER ENERGY ALONG TRACK
21 hsprtrk HSTRACK_PRESHOWER_E PRESHOWER ENERGY "Note definition is exp. dep."
22 hsbeta HSBETA HMS e- velocity based on avg scintillator hit time
23 hsdedx1 HSDEDX(1) energy deposited in scin plane 1 by this track
24 Q2 hsbigq2 x momentum transfer squared Q2 = -q2
25 q3_2 hsq3 x magnitude squared of 3 momentum transfer
26 n_thetaq n_theta_q x q angle in nDet transport coordinate
27 n_phiq n_phi_q x q out of plane angle in nDet transport coord
28 theta_pq n_theta_pq x lab angle between proton (from deuteron) and q
29 theta_np n_theta_np x CM angle between n-p axis and q-vector? ? angle between n-p relative momentum w.r.t. q vector in COM
30 ntrk_N float(numtracks) number of tracks found in nDet
31 ntrk_PID ntrk_PID particle id of chosen nDet track -- complex!!!
32 ntrk_t ntrk_time meantime of first hit on chosen track extrap to plane 3!
33 ntrk_E ntrk_energy total energy of chosen track sum of bar energies -- calibrated!!!
34 ntrk_p ntrk_p_tof TOF based nucleon momentum
35 ntrk_dx ntrk_dx nDet track slope in x
36 ntrk_dy ntrk_dy nDet track slope in y

Notes:
hmscorr (item 18) this quantity seems very useful but the calculation looks flawed.
Anyone feel qualified to comment?
q (item 16, 24, 25, 26, 27) q = k - k' where k is (gebeam,0,0,gebeam) and k' is HMS electron (hsenergy,hsp(3))
prior calculations (in order):
gebeam=sqrt(gpbeam**2 + mass_electron**2)
gebeam = gebeam - geloss
gpbeam = sqrt(gebeam**2 - mass_electron**2)
hsp = hp_tar(hsnum_tartrack)
hsenergy = sqrt(hsp*hsp+hpartmass*hpartmass)
hsenergy = hsenergy + hseloss
hsp = sqrt(hsenergy**2-hpartmass**2)
theta_pq (item 28) calc based on hsthetaq, hsphiq, n_theta_q, n_phi_q, ntheta_lab, ntrk_dx, ntrk_dy
theta_np (item 29) calc based on ntrk_p_tof, theta_pq, hs_qvec and hsq3

 

(frw) 7-2003