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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

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physics from hera b

Physics from HERA-B

Outline

  • Data samples
  • Physics topics
  • Pentaquark searches
  • y(2S) production
  • A –dependence
  • bb cross section
  • Summary

58th PRC Open session, October 28th, 2004

M. Mevius, DESY Hamburg

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58th PRC M.Mevius

data samples
Data samples

Minimum Bias data

200 M events on C,Ti,W

1000 ev/s > 1TB/day

Dilepton triggered data

150 M dilepton trigger events

300 000 J/ (>1000 per hour)

15 000 c

5 000 (2S)

35 M

Hard photon trigger

58th PRC M.Mevius

topics under study
Topics under study
  • Upper limit on BR(D0m+m-) (Phys.Lett.B596:173-183,2004)
  • Pentaquark searches (pKs, Xp) (hep-ex/0408048)

accepted by Phys. Rev. Lett.

  • Inclusive bb cross section
  • Upsilon cross section
  • Production of f and K* mesons
  • y(2S) production
  • D+/D0 production ratio
  • J/y cross section in MB

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58th PRC M.Mevius

topics cont d
Topics cont’d
  • Hard photon production
  • L0 polarization
  • cc production
  • A dependence charmonium production
  • J/y differential distributions
  • V0 and hyperon production
  • Jet production

58th PRC M.Mevius

searches
+,-- Searches

 mass

pK0s mass

NA49

HERA-B

UL(95%)

--

UL(95%)

mass GeV/c2

1.4 1.475 1.55 1.625 1.7

(hep-ex/0408048) accepted by Phys. Rev. Lett.

Counts

Counts

B d/dy b/C

B d/dy b/C

UL(95%)Bd/dy|y=0 =

4-16 b/N

@ 1521-1555 MeV/c2

+ / (1520) < 3 – 12 %

UL(95%)Bd/dy|y=0 =

2.5 b/N @ 1862 MeV/c2

-- / -< 3/B%

-- / (1530)0< 4/B%

58th PRC M.Mevius

y 2s j y production ratio
y(2S) / J/y Production Ratio

Br’·s(y’)

[%]

Br·s(J/y)

√s

preliminary

Preliminary results for

A

preliminary

58th PRC M.Mevius

y 2s differential distributions
y(2S) differential distributions

dσ/dpT2

xF < 0

e+e-

dσ/dxF

preliminary

preliminary

preliminary

m+m-

preliminary

58th PRC M.Mevius

j y a dependence
J/y A dependence
  • only 1 target config (C-W)
  • ~15 % of m+m– sample

similar results for e+e-

  • Hera-B normalization
  • Statistical errors only

preliminary

I1I2

I1I2

preliminary

PT

58th PRC M.Mevius

bb production

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bb production

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b(b)  B  J/ + X

J/  m+m- ; e+e-

Measurement relative to direct J/ production

to minimize trigger/reconstruction uncertainties

R= relative efficiency1

  • B Selection:
    • Lepton impact to the wire
    • Distance of J/ to wire

B selection eff. from MC 30-45%

58th PRC M.Mevius

bb production1

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bb production

preliminary

preliminary

Full statistics

20% sys. error under investigation

main contribution:

Br(bbJ/X) = 2.320.20%

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E771/E789 : scaled to 41.6 GeV

(J/)=357 ± 2 ± 36 nb/nucleon

58th PRC M.Mevius

summary
Summary
  • Good data quality
  • Several QCD related results expected
  • Preliminary results on most topics presented at conferences (>40)
  • 2 papers finished

(BR(D0m+m-) (UL),pentaquark (UL))

  • Publication on advanced analyses in preparation

(bb, U, D+/D0, f/K*, J/y, y(2S),...)

  • Other topics could lead to publication, manpower permitting
  • Analysis will continue until end 2005

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58th PRC M.Mevius

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