1. Status of the HERA-B Analysis 58th PRC Open session, May 26, 2005
Hermann Kolanoski
Humboldt Universität zu Berlin and DESY Zeuthen
for the HERA-B Collaboration
Data samples
Physics topics
Selected topics:
J/y cross section
y(2S) production
A-dependence of J/y production
c production
Summary 1
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

2. H.Kolanoski - Status report HERA-B - PRC59
Data samples
Analysis of data taken from Oct to Feb. 2003
150 M di-lepton trigger events
210 M minimum bias events
35 M hard photon trigger events
60 M “glueball” trigger events
 J/ψ: e+e- + +-
Different target wires, mainly C, Ti, W
proton-nucleon CM energy:
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

3. H.Kolanoski - Status report HERA-B - PRC59
Analysis Topics
published
(2002/03 only)
Upper limit on BR(Do  ) [Phys.Lett.B596: ,2004]
Pentaquark limits (pKS, ) [Phys.Rev.Lett. 93 (2004) ]
bb production cross section
 production cross section
Production of  and K* mesons
J/ production cross section
D+/Do production ratio
Production ratio (2S) / J/
J/ differential distributions
Charmonium production A-dependence
c production, A dependence
high-pt photons
 polarization
Vo differential and total cross section
Hyperon production
Deuteron/anti-deuteron production
Bose-Einstein correlations
Jet production
needs J/ ref. cross section
draft stage
analysis note
in preparation
preliminary
results
available
needs
more work
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

4. J/y Cross Section from Min. Bias Data
relatively low statistics, but no trigger uncertainty
e+e-
+-
A lot of work for lumi studies;
publication in preparation W
(prelim.) Ti
average over A with
α = 0.960.01 fixed
HERA-B ~1.7 x higher than E771 / 789
extrapolated to this energy region (!?) C A
Important for cross section normalization of di-lepton triggered data
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

5. Study of J/ Cross Section Parametrisations
Fit of cross section data
currently studied with F.Maltoni
using NRQCD model
Fits rather stable w.r.t. changes in
model input (PDF’s, ME’s, ..)
Biggest problem:
inconsistent exp.data
(prelim.,
study ongoing)
(previously from E771 and E789: (357  8  27) nb/nucleon)
 1.44
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

6. H.Kolanoski - Status report HERA-B - PRC59
Results for Beauty Cross Sections have to be scaled by new J/ reference cross section
(prelim.)
Plots still normalized to
J/ from E771 and E789
will change by ~ 1.4
(prelim.)
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

7. H.Kolanoski - Status report HERA-B - PRC59
Study of Charmonium Suppression as input for QGP searches in heavy ion collisions
Kinematical distributions (xF, pT, polarization) derived from:
- NRQCD for nucleon-nucleon reactions
- models for nuclear effects in pA reactions p e+ e-
J/ xF
Lf [fm]
0.2 20
0.0 7
-0.2 2
xF measures
the formation length
of the ccg state:
Lf  0.3 fm  
scc =s0  Aa
a ≠ 1  “suppression”
xF > 0 : ccg forms a bound state outside the nucleus
xF < 0 : ccg forms a bound state inside the nucleus
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

8. A dependence of J/ Production : (xF), (pT)
dominant syst.: “wire sharing”;
~2% decrease to ~1% (?)
2-wire runs (C, W), +- data:
HERA-B now
absolutely
normalized
extending the range of
measurements to xF = –0.35
Systematic studies ongoing
electron channel being finalized
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

9. y(2S) Production: s(y(2S)) / s(J/y)
+- data: W C Ti
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

10. H.Kolanoski - Status report HERA-B - PRC59
xF distributions
preliminary
preliminary
preliminary
Ratio:
In agreement with NRQCD
almost constant vs xF
fitted by a + b·|xF|
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

11. H.Kolanoski - Status report HERA-B - PRC59
Dependence on pT
preliminary
preliminary
Power-low is suitable for the fitting
(2S) appears to have a wider pT distribution
 nuclear effects different for radial excitation?
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

12. A- and s-Dependence of s(y’(2S)) / s(J/y)
Agrees with E866 value:
a(y(2S)) - a(J/y)=-0.026±0.005
preliminary
Results from +- data:
prelim.
R = B Ds(y(2S)) / B Ds(J/y)
C : ( / ) %
W: ( / ) %
Ti: ( / ) %
All: ( / ) % ,
(as one sample, A-dep. from E866)
preliminary
Similar results from e+e- data
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

13. c / J/ production ratio
observed in radiative decay
Background shape
from event mixing
+- channel, results from full data set now available
all targets
carbon
tungsten
m = m(l+l-) – m(l+l-) [GeV/c2]
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

14. c production: results
R(c) = 0.21±0.05 (prel.)
Systematic studies ongoing
background determination
 efficiency
electron channel (similar results)
dependence on polarization
The efficiencies for all possible polarization states have been calculated and differ by less than 10%.
from only 10% of 2002/03 data z
ECMS (GeV)
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59

15. H.Kolanoski - Status report HERA-B - PRC59
Conclusion
HERA-B has a considerable list of interesting topics under study which should be published.
The number of active collaboration members is decreasing as expected but the main analysis topics should be reasonably covered.
The goal is to produce draft publications by end of this year for most of the topics (O(10), for sure 4 publications this summer)
May 26, 2005
H.Kolanoski - Status report HERA-B - PRC59