1. Physics highlights from Hera-B
57th PRC Open session, May 27th, 2004
Data samples and triggers
Results from MB data
Results from dilepton trigger data
Summary
M. Villa, INFN Bologna

2. Data and triggers Data taking: 30. Oct 2002 - 3. Mar 2003
210 M minimum bias events
Logging rates: 1 kHz (1.7 TB/d)
150 M dilepton triggered events with ~300k J/
J/ rates: / hour
90 M hard photon + Glueball trigger 2
57th Desy PRC

3. Minimum bias topics Production of  and K* mesons
Vo differential and total cross section
o polarization
Hyperon production
Pentaquark searches (pKS, )
Bose-Einstein correlations
D+/Do production ratio  
See last PRC
57th Desy PRC

4. Strangeness production
KSππ
Λpπ
RICH PiD
large statistics:
Ks ~ 3.4 x 106 Ks σ ~ 4,9 MeV
Λ ~ 1.4 x σ ~ 1,8 MeV
Λ(1520) ~ σ ~ 8 MeV
Λ(1520) pK-
Good kaon ID: 10< p <60 GeV
Good proton ID: 20< p <60 GeV
57th Desy PRC

5. Production of  and K* KK : 52600 events K*o Kπ + cc:
Differential cross sections ddpt2
measured for three nuclei
(12C, 48Ti, 184W) up to 12 GeV2/c2 in pt2
Cronin effect observed
for resonances
KK :
52600 events
K*o Kπ + cc:
events
57th Desy PRC

6. Pentaquark searches (pKS)
No evidence of resonances in the mass region around 1530 GeV.
The upper limit on the particle yield ratio relative to 1520 is:
+/1520 < 0.02 (95% C.L.)
Hermes: +/1520  1.6  3.5
(same BR for + decays assumed)
Evaluation of the nuclear cross section upper limit in progress
57th Desy PRC

7. Pentaquarks in ? Ξ π+ + Ξ+π Ξ π + Ξ+π+ Statistics:
Mass GeV/c2
1.2
1.3
1.5
1.4
x103 2 4 6 Ξ0
Ξ π+ + Ξ+π
Ξ±→π±
Ξ π + Ξ+π+
no narrow signal visible!
green area: background from event mixing
Ξπ invariant mass (GeV/c2)
Statistics:
~ Ξ-, σ ~ 2,6 MeV
~ Ξ+,σ ~ 2,6 MeV
Upper limits (95% cl):
Ξ--(1862) / Ξ0(1530) < Ξ++(1862) / Ξ0(1530) < 0.058
57th Desy PRC

8. Dilepton trigger topics
Production ratio of J/ and ’
J/ and ’ differential distributions
Charmonium production A dependence
c production, A dependence
bb production cross section
 production cross section
Upper limit on BR(Do  )
See last PRC  
See last PRC 
57th Desy PRC

9. c production R(c) = 0.21±0.05 c  J/   +-   ≈ 0.4
Systematic studies ongoing
In 15% of  sample ≈1300 c
≈10 k in full sample exp.
R(c) = 0.21±0.05
N(c) = 38074 (both +-, e+e-)
R(c) = 0.320.060.04 
2000
M (GeV/c2)
57th Desy PRC

10. bb production Analysis of 2002/03 data:
35% of ee and  statistics
Expect NB ~ 100 for full sample
J/ acceptance: -0.35<xF< (90% of bb cross section)
Preliminary results of both channels are compatible
1.5  lower than 2000 measurement
preliminary
57th Desy PRC

11. Limit on BR(Do) D° BR(Do) < 2.0 x 10-6 (90% cl)
sideband
3 evt
sideband
BR(Do) < 2.0 x 10-6 (90% cl)
DESY
hep-ex/
Submitted to Phys Lett B
CDF: BR(Do) < 2.5 x10-6
Phys.Rev. D 68 (2003)
Currently best upper limit
18 evt
6 evt
57th Desy PRC

12. Summary High quality of data collected
A large variety of physics topics addressed
( s, c, b and exotics)
Preliminary results on most topics presented
Publications on the most advanced analyses in preparation (D° , , bb, , D+/D°, c ,...)
Several other topics could lead to publication, manpower permitting
57th Desy PRC