Study of D*(2010)+- Production in ep Collisions at HERA

Abstract

We report the first observation of charmed mesons with the ZEUS detector at HERA using the decay channel ${\rm D}^{*+}\rightarrow (\Do \rightarrow {\rm K}^-π^+)π^+$ (+ c.c.). Clear signals in the mass difference $\Delta M$=$M$(D${}^{\ast }$)--$M$(D${}^0)$ as well as in the $M(K\pi )$ distribution at the D${}^0$ mass are found. The $ep$ cross section for inclusive \DSpm\ production with $Q^2<4~\GeV^2$ in the $\gamma p$ centre-of-mass energy range $115<W<275$ \GeV\ has been determined to be $(32\pm 7_{-7}^{+4})$ nb in the kinematic region \mbox{\{$p_T(\DS)\geq $ 1.7 \,\GeV, $|η(\DS)| < 1.5 $\}}. Ex\-tra\-po\-la\-ting outside this region, assuming a mass of the charm quark of 1.5 \GeV, we estimate the $ep$ charm cross section to be $\sigma (ep\to c\bar{c}X)=(0.45\pm 0.11_{-0.22}^{+0.37})\mu \mathrm{b}$ at \mbox{$\sqrt{s}=296$}~\GeV\ and $⟨W⟩=198$ \GeV. The average $\gamma p$ charm cross section \mbox{$\sigma (\gamma p\to c\bar{c}X)$} is found to be \mbox{$(6.3\pm 2.2_{-3.0}^{+6.3})\mu \mathrm{b}$} at $⟨W⟩=163$ \GeV\ and \mbox{$(16.9\pm 5.2_{-8.5}^{+13.9})\mu \mathrm{b}$} at $⟨W⟩=243$ \GeV. The increase of the total charm photoproduction cross section by one order of magnitude with respect to low energy data experiments is well described by QCD NLO calculations using singular gluon distributions in the proton.

19 pages, latex, 3 figures appended as uuencoded file

References in corpus (2)

• Heavy Quark Correlations in Photon-Hadron Collisions
• On the Determination of the Gluon Density of the Proton from Heavy-Flavour Production at HERA

Cited by in corpus (28)

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• D* Production in Deep Inelastic Scattering at HERA
• Charm quark and D^* cross sections in deeply inelastic scattering at DESY HERA
• Selected Science Opportunities for the EicC
• Measurement of charm fragmentation ratios and fractions in photoproduction at HERA
• Photoproduction of $D^{\ast \pm }$ Mesons in $ep$ Collisions at HERA
• Accessing the real part of the forward $J/\psi$-p scattering amplitude from $J/\psi$ photo-production on protons around threshold
• The proton's gluon distribution
• Cross Sections for Charm Production in $ep$ Collisions: Massive versus Massless Scheme
• Probing the Parton Densities of Virtual Photons at ep Colliders
• Measurement of Inclusive Ds+- Photoproduction at HERA
• Resolved Photon Processes
• Comparison between the various descriptions for charm electroproduction and the HERA-data
• How open charm production and scaling violations probe the rightmost hard BFKL pole exchange
• Diffractive Photoproduction of D*+/-(2010) at HERA
• Beauty photoproduction using decays into electrons at HERA
• Differential Cross Sections of D*+- Photoproduction in ep Collisions at HERA
• Heavy Quark Hadroproduction in $k_T$-Factorization Approach with Unintegrated Gluon Distributions
• Heavy-Quark Production in the Target Fragmentation Region
• Associated J/psi + gamma Photoproduction as a Probe of the Colour-Octet Mechanism
• Diffractive beauty photoproduction as a short distance probe of QCD pomeron
• Systematics of Heavy Quark Production at HERA
• Exclusive photoproduction of charmed $D^{\ast }$ vector mesons, $\gamma +N\to Y_c+{\bar{D}}^{\ast }$, $Y_c={\Lambda }_c^{+}$ or ${\Sigma }_c$
• Heavy Quarks in Polarized Structure Functions
• Measurement of D*+/- diffractive cross sections in photoproduction at HERA