Evidence for X(3872) in Pb-Pb collisions and studies of its prompt production at √s NN = 5.02 TeV
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Type :
Article
Publication Status :
Published
Access :
Attribution 4.0 International
openAccess
http://creativecommons.org/licenses/by/4.0/
openAccess
http://creativecommons.org/licenses/by/4.0/
Abstract
The first evidence for X(3872) production in relativistic heavy ion collisions is reported. The X(3872) production is studied in lead-lead (Pb-Pb) collisions at a center-of-mass energy of
√
s
NN
=
5.02
TeV
per nucleon pair, using the decay chain
X
(
3872
)
→
J
/
ψ
π
+
π
−
→
μ
+
μ
−
π
+
π
−
. The data were recorded with the CMS detector in 2018 and correspond to an integrated luminosity of
1.7
nb
−
1
. The measurement is performed in the rapidity and transverse momentum ranges
|
y
|
<
1.6
and
15
<
p
T
<
50
GeV
/
c
. The significance of the inclusive X(3872) signal is 4.2 standard deviations. The prompt X(3872) to
ψ
2
S
yield ratio is found to be
ρ
Pb
−
Pb
=
1.08
±
0.49
(
stat
)
±
0.52
(
syst
)
, to be compared with typical values of 0.1 for
p
p
collisions. This result provides a unique experimental input to theoretical models of the X(3872) production mechanism, and of the nature of this exotic state.
Source :
Physical Review Letters
Date :
2022-01-19
Volume :
128
Issue :
3
Publisher :
American Physical Society
URI
http://hdl.handle.net/10679/8553https://journals.aps.org/prl/abstract/10.1103/PhysRevLett.128.032001
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