Hera-B Physics results Data of the year 2000 limited statistics 2.Commissioning:
Physics from HERA-B
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28-10-2004 58 th PRC M.Mevius 1 Physics from HERA- B 58 th PRC Open session, October 28 th , 2004 M. Mevius, DESY Hamburg Outline • Data samples • Physics topics • Pentaquark searches • (2S) production • A –dependence • bb cross section • Summary -
description
Physics from HERA-B. Outline. Data samples Physics topics Pentaquark searches y (2S) production A –dependence bb cross section Summary. 58 th PRC Open session, October 28 th , 2004 M. Mevius, DESY Hamburg. -. Data samples. Minimum Bias data. 200 M events on C,Ti,W - PowerPoint PPT Presentation
Transcript of Physics from HERA-B
28-10-2004 58th PRC M.Mevius 1
Physics from HERA-B58th PRC Open session, October 28th, 2004
M. Mevius, DESY Hamburg
Outline• Data samples
• Physics topics
• Pentaquark searches
• (2S) production
• A –dependence
• bb cross section
• Summary
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Data samples
200 M events on C,Ti,W1000 ev/s > 1TB/day
Minimum Bias data
Dilepton triggered data
150 M dilepton trigger events 300 000 J/ (>1000 per hour) 15 000 c
5 000 (2S)
Hard photon trigger 35 M
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Topics under study
• Upper limit on BR(D0(Phys.Lett.B596:173-183,2004)
• Pentaquark searches (pKs, (hep-ex/0408048)
accepted by Phys. Rev. Lett.
• Inclusive bb cross section• Upsilon cross section• Production of and K* mesons• (2S) production• D+/D0 production ratio• J/ cross section in MB
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Topics cont’d• Hard photon production• 0 polarization
• c production
• A dependence charmonium production• J/differential distributions• V0 and hyperon production• Jet production
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+,-- Searches
UL(95%)Bd/dy|y=0 = 4-16 b/N
@ 1521-1555 MeV/c2
+ / (1520) < 3 – 12 %
UL(95%)Bd/dy|y=0 = 2.5 b/N @ 1862 MeV/c2
-- / - < 3/B % -- / (1530)0 < 4/B %
B d
/d
y b
/C
B d
/d
y b
/C
Co
un
ts
C
ou
nts
NA49
HERA-B
UL(95%)
mass
1.4 1.475 1.55 1.625 1.7
pK0s mass
UL(95%)
mass GeV/c2
(hep-ex/0408048) accepted by Phys. Rev. Lett.
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(2S) / J/ Production Ratio
2 2
2
(2 ( S) ( S) J/
J/ J/ ( S)
BR( S) l l ) N
BR(J/ l l ) N
Preliminary results for
Br·(J/)
Br’·(’)[%]
Target electron muon
C 1.6 ± 0.2 1.65 ± 0.1
W 1.8 ± 0.4 1.54 ± 0.2
√s
A
preliminary
preliminary
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(2Sdifferential distributions
preliminary
preliminary
dσ/dpT2
preliminary
preliminary
xF < 0 dσ/dxF e+e-
+-
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J/A dependence
I1I2
; N/( )A LpA pN
N1ln
ln( / ) NC CW
W C C W W
L
A A L
only 1 target config (C-W) ~15 % of+– sample
similar results for e+e-
Hera-B normalization Statistical errors only
preliminary
preliminary
I1I2
PT
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bb production
B Selection: Lepton impact to the wire
Distance of J/ to wire
b(b) B J/ + XJ/ +- ; e+e-
)/(
1
//
XJbbBrn
nzBRJ
BJbb
R= relative efficiency1
B selection eff. from MC 30-45%
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Measurement relative to direct J/ production to minimize trigger/reconstruction uncertainties
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Full statistics
0.027 0.004 0.005/
bb
J
preliminary
20% sys. error under investigationmain contribution: Br(bbJ/X) = 2.320.20%
bb production
E771/E789 : scaled to 41.6 GeV(J/)=357 ± 2 ± 36 nb/nucleon
preliminary
9.8 1.4 2.0 nb/nucleonbb
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Summary
• Good data quality• Several QCD related results expected• Preliminary results on most topics presented at
conferences (>40)• 2 papers finished
(BR(D0(UL),pentaquark (UL))• Publication on advanced analyses in preparation
(bb, , D+/D0, K*, J/, (2S),...)• Other topics could lead to publication, manpower
permitting• Analysis will continue until end 2005
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