Charm (and Beauty) Production at the Tevatron Page: 1 of 10
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Charm (and Beauty) Production at the Tevatron
Jonas Rademacker on behalf of the CDF and the DO Collaboration
University of Bristol, H H Wills Physics Laboratory, Bristol, BS8 1 TL, UK
We present recent results on heavy flavour production at Tevatron Run II for typically ~ 1 fb--
of analysed pp data at /s = 1.96 TeV. This includes results on single and correlated open charm
and bottom cross sections, charm pair production kinematics, J/0, 0(2S) and XcJ cross sections
and polarisation measurements in J/0, 0(2S), T(1S), and T(2S).I. INTRODUCTION
II. THE TEVATRON, CDF AND DO
A. The Tevatron Run II
The large bb and cc cross section at V6 = 1.96 TeV
pp makes the Tevatron a unique place for the study
of the production and decay of heavy flavour. Al-
ready in Run I, heavy flavour production measure-
ments challenged theory, finding heavy flavour pro-
duction cross sections significantly higher than pre-
dicted by Next-to-Leading-Order (NLO) QCD calcu-
lations (see for example [1] and [2]). The discrepancy
between data and theory was particularly dramatic in
the quarkonium production, where the "Colour Sin-
glet Model" leading-order QCD calculation underes-
timates the measured cross section by more than an
order of magnitude (see e.g.[3]).
Since the first hadroproduction measurements in
Run I, a number of theoretical advances have been
made. Fixed-Order Next to Leading Logarithm
(FONLL) calculations [4], describe the open charm
and b production cross sections well. Competing mod-
els have been put forward that describe the observed
quarkonium production rates and PT spectra well, but
disagree on their results for quarkonium polarisation.
There has also been dramatic experimental
progress. In Run II, which started in 2001, the Teva-
tron collides p and p at unprecedented luminosity and
energy, and the DO and the CDF experiment have
undergone significant upgrades, many of them opti-
mising the detector for flavour physics. In this paper,
we summarise the heavy flavour production measure-
ments in Run II at DO and CDF, and compare them
with theoretical predictions.
As we will see below, heavy flavour production at
hadron colliders is a vibrant field which is lead by ex-
periment rather than theory. A particular challenge
for theory is the quarkonium polarisation, for which
we present new results from the Tevatron in this pa-
per.
All numbers, unless accompanied by a reference to
a journal publication, are preliminary.The Tevatron in Run II collides protons and an-
tiprotons at a centre of mass energy of 1.96 TeV
with a bunch crossing every 396 ns at each interac-
tion point. Some of the bunches are by design empty,
so while the detectors have to be able to cope with
peak rates of 2.5 MHz, the average collision rate is
~ 1.7 MHz. Since the start of data taking, the Teva-
tron has delivered more than 3 fb- of integrated lumi-
nosity at each interaction point, and is now reaching
peak luminosities of typically 2- 1032 cm-2s-1, with
the best runs exceeding 2.8- 1032 cm-2s-1. Two gen-
eral purpose detectors take data at the Tevatron, CDF
and DO. Both collaborations have analysed approxi-
mately 1 fb-i of nearly 3 fb-i each has on tape.
B. The CDF and DO Detectors
Both the CDF and the DO collaboration have a
strong heavy flavour physics programme, and in the
last upgrade many features have been added to the de-
tectors to facilitate this programme. These features
include precise vertexing, extended coverage, and
sophisticated read-out electronics and triggers. A de-
scription of the DO detector can be found at [5] and
of the CDF detector at [6].
The same detector characteristics that make DO
and CDF powerful B physics experiments, also pro-
vide the basis for a wide-ranging charm physics pro-
gramme. The feature that makes DO stand out as
a heavy flavour experiment particularly is its large
coverage [7], up to 1771 < 2. CDF's most distinctive
detector element for B and charm physics is its fully
hadronic track trigger [8].
C. Triggers
Once every 396 ns there is a bunch crossing at each
Tevatron interaction point, typically resulting in a
very busy event; only a few tens of a per mill (ca
6- 10-4 at CDF) of those events can be written to
tape and analysed in detail, the vast majority will be0)
CD
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Rademacker, Jonas & U., /Bristol. Charm (and Beauty) Production at the Tevatron, article, November 1, 2007; Batavia, Illinois. (https://digital.library.unt.edu/ark:/67531/metadc898733/m1/1/: accessed April 25, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT Libraries Government Documents Department.