Heavy Flavour Production at HERA-BPresented by Andrey Bogatyrev (bogatyr@mail.desy.de) 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