heavy flavour production at hera-b
DESCRIPTION
J/ . e +. preliminary 2002/2003 data (di-muon sample). p. e -. -0.35 < x F < 0.1 0 < p T < 6 GeV. pA bb X b J/ ψ Y e + e - / + - Y. ( × 10 -4 ). E789 (Au). ( × 10 -3 ). background: mixed events. ( × 10 -2 ). E771 ( p- Si ). NRQCD. - PowerPoint PPT PresentationTRANSCRIPT
Heavy Flavour Production at HERA-BPresented by Andrey Bogatyrev ([email protected]) for the HERA-B collaboraton
J/ cross section in minimum bias data
J/ production in pA collisions
[GeV
-2]
E789 (Au)E789 (Au)E789 (Au)E789 (Au)
HERA-B (C)HERA-B (C)HERA-B (C)HERA-B (C)
E771 E771 (Si)(Si)
E771 E771 (Si)(Si)
E672/E706 (Be)E672/E706 (Be)E672/E706 (Be)E672/E706 (Be)
((××1010-4-4))
((××1010-1-1))
((××1010))
pT [GeV]
HERA-B (Ti)HERA-B (Ti)HERA-B (Ti)HERA-B (Ti)
HERA-B (W)HERA-B (W)HERA-B (W)HERA-B (W)
((××1010-2-2))
((××1010-3-3))2
1
Tdp
d
<p
T>
[GeV
/c]
A
C Si Ti AuWBeen
trie
s/(1
0 M
eV
/c2)
m(μ+μ-γ)-m(μ+μ-) [GeV/c2]
preliminary2002/2003 data
(di-muon sample)
background: mixed events
after background subtraction
[GeV]s
expected final
precisionCDF CDF ((p-pp-p))
ISR ISR ((p-pp-p))
E771 E771 ((p-p-SiSi))
E705 E705 ((p-p-LiLi))
E369/ E369/ 610/ 610/ 673 673 ((p-p-BeBe))
2002/3 2002/3 prelim.prelim.
ππ-A-A
HERA-BHERA-B
20002000
Mass difference M=M(l+ l- ) - M(l+ l- )
production
Fit: A· ((1S) + (2S) + (3S)) + B · Drell-Yan + combinatorial
(1S):(2S):(3S) fixed to E605 From MC From like-sign pairs
<pT> grows logarithmically with A:
T
ln0.0246 0.0026
d
d pA
= ±
Cronin effectDifferential distributions in xF and
pT
A-dependence
= 0.969 ± 0.003stat ± 0.021sys
<pT> grows with s:
<pT> 0.8 + 0.01·s
Reconstructed mass spectra
c J/ production
pA bb X b J/ψ Y e+e-/+- Y
Hera-B was a fixed target spectrometer operating at the HERA proton beam at DESY (Hamburg). The main fields of interest of the experiment are the study of charm and beauty production in pA interactions at √s = 41.6 GeV. During the data taking period 2002/3, huge samples of high quality data were recorded with different target nuclei (C, Ti, W).
Interaction of 920 GeV/c protons with nuclei of
target wires (C, Ti, W)
Running time ~480 h Minimum bias events ~210 Mio Dilepton trigger evens ~150 Mio “Glueball” trigger events ~60 Mio Hard photon trigger events ~10 Mio Peak DAQ rate (MinBias) ~1kHz J/ rate (events/time) ~1000/hour
High rate forward spectrometer (10 MHz interaction rate) Angular coverage: 15 - 220 mrad in bending plane, 15 - 160 mrad in vertical plane Designed for high interaction rates Particle identification (e, , , K, p) Hardware track-trigger for lepton pairs (ee, ) Multiple trigger levels: electron and muon pretriggers, hardware first level trigger, software second level trigger. On-line event reconstruction with PC-farm
The Hera-B detector
p
e+
e-
J/
Introduction
2002/3 data taking:
Fit the existing experimental data using function based on NRQCD calculations at NLO Scale parameter: 0 = 2mc with mc = 1.5 GeV 0 = F(factorization) = R(renormalization) PDF sets: MRST2002nlo and CTEQ6m Color-singlet matrix elements from potential model calculations Color-octet matrix elements extracted from CDF data Introduce free scaling parameters for S-wave matrix elements J/ and (2S) = fraction of color-octet contribution required relative to CDF results
0.01 < J/ < 0.31 and 0.02 < (2S) < 0.14 Required color-octet contribution about 10% of that for Tevatron data. Supports HERA ep data which do not need large octet contributions.
Test of universality of non-perturbative
matrix elements of quarkonia
fit results at s = 41.6 GeV:
Conclusions
CEM
NRQCD
better than current PDG value
improvement of B‘():
PHYS. REV. D 73, 052005 (2006)PHYS. LETT. B 638 (2006)
F. Maltoni et al.
PHYS. LETT. B 638, 202 (2006)
PHYS. LETT. B 638, 407 (2006)
Open charm in minimum bias data
(2S) production Open beauty production
,
2
, J /1
J / J /
BR( J/ )( ) c i c
c
c iic
NR
N
Mass spectra after detachment cuts
)/(
1
//
JbbBrn
nR
zBRJ
B
J
bb
R = 0.032 0.005stat 0.004sys
-0.35 < xF < 0.1
0 < pT < 6 GeVfor
(2S) / J/ ratio
J/ + -
100 12J/ e+ e-
57 13
R(c)
Submitted to EPJC