dilepton analysis status run-10 au+au @ 200 gev
DESCRIPTION
Dilepton analysis status Run-10 Au+Au @ 200 GeV. Dmitry Kotov Victor Riabov Yuriy Riabov (PNPI). Event and track selection. Basic cuts. Dataset: Run-10 Au+Au @ 200 GeV (pro.84), run#300105-310354. Cuts: DC deadmap (heavy-light meeting, 01/27/2011); Track quality: 31 || 51 || 63; - PowerPoint PPT PresentationTRANSCRIPT
Dilepton analysis status
Run-10 Au+Au @ 200 GeV
Dmitry Kotov
Victor Riabov
Yuriy Riabov
(PNPI)
2
Event and track selection. Basic cuts.Dataset: Run-10 Au+Au @ 200 GeV (pro.84), run#300105-310354
Cuts: • DC deadmap (heavy-light meeting, 01/27/2011);• Track quality: 31 || 51 || 63;• |bbcvertex| < 20 cm;• Trigger:
BBCLL1(>1 tubes) || BBCLL1(>1 tubes) narrowvtx;• pT of unidentified track: 0.2 < pT < 10 GeV/c;• |zed| < 75 cm;• Ghost rejection for pairs (AN673, AN694):
if ( fabs(dzed)<6.0 && fabs( dphi - (0.13*dalpha) ) < 0.015 ) return false; if ( fabs( dphi - (0.04*dalpha) ) < 0.015 ) return false; if ( fabs( dphi - (-0.065*dalpha) ) < 0.015 ) return false;
• Cut for central support of DC and RICH (AN926).
3
DC dead map (I)DCE before DCE after
Side0
Side1
6X2, 7X2
8X1
8X1
Alp
ha
board
9X2
4
DC dead map (II)DCW before DCW after
Side0
Side1
9X2
12X1X2 13X2
8X2
4X1X2
9X28X2
13X1X2
Alp
ha
board
5
eID cuts.eID cuts:
• n0 > 3;• chi2n <= 10;• disp < 5;• |dep| < 2;• Cut for RICH ghosts (AN840):
( fabs(xphi[i] - xphi[j]) < 0.12 && fabs(xz[i]-xz[j]) < 25 );
• |emcsdphi_e| < 2 && |emcsdz_e| < 2;
Optional eID cuts:• |hbdsdphi| < 2.5 && |hbdsdz| < 2.5;• hbdcharge > 9, 12, 15, 21;
HBD EN2 removal:• 180 < atan(hbdy/hbdx) < 202.5 and hbdz > 0.
6
EMCal matchings
How to
• Accumulate TH2F’s emcdphi vs zed, emcdz vs theta for e+/e-;
• Slice into zed (theta) bins, Gaussian fit, extract centroids and sigmas;
• Fit centroids and sigmas with p0(pT)+p1(pT)*zed+p2(pT)*zed2:
• Except for the fit of emcdz mean: p0(pT) + p1(pT)*tan(zed);
• Fit p0, p1, p2 with c0+c1/pT+c2/pT2 to remove pT dependence;
emcsdphi_e = (emcdphi – centroid(zed, pT))/sigma(zed, pT)
emcsdz_e = (emcdz – centroid(theta, pT))/sigma(theta, pT)
7
EmcsdphiMean
SigmaRemove z-dependence
Remove pT dependence
p0
p1
p2
p0
p1
p2
Mean Sigma
Sigma
emcsdphi_e =
(emcdphi –centroid(zed, pT))
/sigma(zed, pT)25 pT bins, 8 EMCal sectors,
2 charges, 2 field orientations
Makes up to 800 histos!
1 sector, e+, +/- field,0.24< pT (GeV/c) <0.26
Remove z-dependence
Mean
Sigma
Mean
Sigma
Remove pT dependence
Mean
Sigma
Remove pT dependence
Mean
Sigma
p0
p1
p2
p0
p1
Sigma
p2
p0
p1
p0
Sigma
p2
p0
p1p1
p0
Sigma
p2
p0
p1
p2
p1
p0
Sigma
p2
p0
p1
Mean
p2
p1
p0
Sigma
p2
p0
p1
8
Emcsdz1 sector, e+, +/- field,0.24< pT (GeV/c) <0.26
Remove z-dependence Remove pT
dependence
Mean
Sigma
Mean
p1
p0Sigma
p2
p0
p1
emcsdz_e =
(emcdz –centroid(zed, pT))
/sigma(zed, pT)
25 pT bins, 8 EMCal sectors,2 charges, 2 field
orientationsMakes up to 800 histos!
9
Sigmalized variables
Emcsdphi, sector 1, +/- field
e+ e-
Mean Mean
SigmaSigma
Emcsdz, sector 1, +/- field
Mean
Sigma
Mean
Sigma
Mean
Sigma
Mean
Sigma
pT (GeV/c)
pT range of parameterizations from 0.1 to 4.0-4.5 GeV/c
10
E/p ratio parameterizations• Accumulate TH2F’s E/p vs pT for e+/e-
candidates;
• Slice into pT bins, Gaussian fit, extract centroids and sigmas and:
dep means and sigmas vs pT (sector 4, +/- field)
Mean, e+
Sigma, e+
Mean, e-
Sigma, e-
dep = (E/p – mean(pT))/sigma(pT)
pT
pT of the slice:0.4 – 0.5 GeV/c
11
HBD matching for e-candidatesHBD acceptance before hbd matching HBD acceptance after hbd matching
“After” histo divided to “before”
• In some phi-zed regions the probablity to have matching is unexpectedly low (~0.1-0.2). Why?
• Need to include this into simulation?
zed
phi
phi
zed
zed
phiphi = atan (hbdy/hbdx)
zed = hbdz
12
20 cm 20 cm,hbd
matching
20 cm, hbd matching,
hbd charge >9
20 cm, hbd matching,
hbd charge >12
20 cm, hbd matching,
hbd charge >15
20 cm, hbd matching,
hbd charge >21
Mass 3.10±0.01 3.10±0.01 3.10±0.01 3.10±0.01 3.10±0.01 3.10±0.01
Width 0.071±0.013 0.073±0.01 0.07±0.01 0.07±0.01 0.071±0.01 0.069±0.01S/B
(2.9-3.3)1/8 1/4 1/4 1/4 1/3 1/3
Min bias invariant mass spectra. J/psi peaks.
20 cm 20 cm, hbd matching
20 cm, hbd matching, hbd charge>9
20 cm, hbd matching, hbd charge>12
20 cm, hbd matching, hbd charge>15
20 cm, hbd matching, hbd charge>21
968.5±91.7 (9.4%) 621.5±53.4 (8.6%) 551.2±50.3 (10%)
503.4±48.3 (10%) 433.6±45.1 (10.4%) 302.9±39.1 (13%)
13
Phi and omega proto-peaks
• There are hints of peaks from omega and phi decays near 0.78 and 1.01:• Invisible without HBD!• Barely visible with HBD matching (|hbdsdphi|<2.5 && |hbdsdz|<2.5);• Best option is HBD matching + hbdcharge > 9.• Further increase of hbdcharge cut (12, 15, 21) impairs the signal.
20cm, hbd matching, hbd charge > 9
14
Low Minv issue
Red – BG (mixing) Black - FG
• How to improve FG behavior at low Minv < 0.3 GeV/c2;
Huge peak near Minv ~ 0 GeV/c2.
• BG shape doesn’t fully agree with FG;
Minv
Cou
nts
15
To do list
• Further work with analysis cuts (phiV);
• Need centrality recalibrator:
Do we have/can we use temporary centrality recalibrator?