Open charm production and asymmetry in pNe collisions at √sNN = 68.5 GeV

Abstract

Abstract A measurement of

$${{D}} ^0$$

D

0

meson production by the LHCb experiment in its fixed-target configuration is presented. The production of

$${{D}} ^0$$

D

0

mesons is studied with a beam of 2.5

$$\,\text {Te\hspace{-1.00006pt}V}$$

Te

V

protons colliding on a gaseous neon target at rest, corresponding to a nucleon–nucleon centre-of-mass energy of

$$\sqrt{s_{\scriptscriptstyle \text {NN}}} = 68.5\,\,\text {Ge\hspace{-1.00006pt}V} $$

s

NN

= 68.5

Ge

V

. The sum of the

$${{D}} ^0$$

D

0

and

$${\hspace{0.0pt}\overline{\hspace{0.0pt}{D}}} {}^0$$

D

¯

0

production cross-section in

$$p\text {Ne}$$

p Ne

collisions in the centre-of-mass rapidity range

$$y^{\star }\in [-2.29, 0]$$

y ⋆

∈

[ - 2.29 , 0 ]

is found to be

$$\sigma _{D^{0}}^{y^\star \in [-2.29, 0]} = 48.2 \pm 0.3 \pm 4.5 \,\upmu \text {b}/\text {nucleon}$$

σ

D 0

y ⋆

∈

[ - 2.29 , 0 ]

= 48.2 ± 0.3 ± 4.5

μ b / nucleon

where the first uncertainty is statistical and the second is systematic. The

$${{{D}} ^0}-{{\hspace{0.0pt}\overline{\hspace{0.0pt}{D}}} {}^0} $$

D

0

-

D

¯

0

production asymmetry is also evaluated and suggests a trend towards negative values at large negative

$$y^{\star }$$

y ⋆

. The considered models do not account precisely for all the features observed in the LHCb data, but theoretical predictions including 1

$$\%$$

%

intrinsic charm and 10

$$\%$$

%

recombination contributions better describe the data than the other models considered.