The charm production is sensitive to early dynamics of the created system in RHIC heavy ion collisions. Dominant process of charm quarks production at RHIC is believed to be initial gluon fusion which can be calculated in the perturbative QCD. Understanding both the charm production total cross section and the fragmentation in p+p collisions is a baseline to further exploring the QCD medium via open charm and charmonium in heavy ion collisions. In this paper we present the first reconstruction of open charm meson $D^{0}$ via the weak decay to K and $π$ mesons in the p+p collisions at $\sqrt{s}$ = 200 GeV. The analysis is based on the large p+p minimum bias sample collected in RHIC year 2009 by the STAR detector. The $D^0$ decay daughter identification was improved by using the data of the newly installed Time-Of-Flight detector with 72% of its designed coverage.
We present an analysis of charm quark fragmentation at 10.6 GeV, based on a data sample of 103 fb collected by the Belle detector at the KEKB accelerator. We consider fragmentation into the main charmed hadron ground states, namely \DZ, \DP, \Ds and \LC, as well as the excited states \DSZ and \DSP. The fragmentation functions are important to measure as they describe processes at a low energy scale, where calculations in perturbation theory lead to large uncertainties. Fragmentation functions can also be used as input distributions for Monte Carlo generators. Additionally, we determine the ave…
The results of a dedicated search for pair production of scalar partners of charm quarks are reported. The search is based on an integrated luminosity of 20.3 fb$^{-1}$ of pp collisions at $\sqrt{s}=8$ TeV recorded with the ATLAS detector at the LHC. The search is performed using events with large missing transverse momentum and at least two jets, where the two leading jets are each tagged as originating from c-quarks. Events containing isolated electrons or muons are vetoed. In an R-parity-conserving minimal supersymmetric scenario in which a single scalar-charm state is kinematically accessi…
The latest results on charm-tagged jets and open-charm production obtained with \mbox{ALICE} at the LHC are presented. The baryon-to-meson ratios for $\mathrm{Λ^+_c}$, $\mathrm{Σ^{0,+,++}_c}$ and $\mathrm{Ξ^{0,+}_c}$ measured in pp collisions at $\sqrt{s}=13\ \mathrm{TeV}$ are discussed. The measurements of the jet-momentum fraction carried by the $\mathrm{D^0}$ meson and $\mathrm{Λ^+_c}$ baryon in pp collisions at $\sqrt{s}=13\ \mathrm{TeV}$ are reported, and the number of leading-parton splittings $n_{SD}$ for $\mathrm{D^0}$-tagged and inclusive jets in pp collisions at $\sqrt{s}=13\ \mathrm…
We present the first measurements of the ratios of cross sections, σ(ppbar -> Z+c jet)/σ(ppbar -> Z+jet) and σ(ppbar -> Z+c jet)/σ(ppbar -> Z+b jet) for the associated production of a Z boson with at least one charm or bottom quark jet. Jets have transverse momentum p_{T}>20 GeV and pseudorapidity |η|<2.5. These cross section ratios are measured differentially as a function of jet and $Z$ boson transverse momenta, based on 9.7 fb^{-1} of ppbar collisions collected with the D0 detector at the Fermilab Tevatron Collider at sqrt(s) = 1.96 TeV. The measurements show significant deviations from per…
Search for the Charmed Pentaquark Candidate Theta_c(3100) in e+e- Annihilations at sqrt(s)=10.58 GeV
我们在质心（c.m.）的e ^+ e ^-相互作用中寻找H1合作组报道的五夸克态候选者，即Theta_c（3100）^0。能量为10.58 GeV，使用SLAC的PEP-II e ^+ e ^-设施的BaBar探测器记录的124 fb-1数据。我们在H1所报道的相同pD ^{*-}衰变模式中没有发现这样一种状态的证据，我们对它的产生截面乘以pD ^{*-}的分支分数作为c. m的函数设定了限制。势头.对应于每个e ^+ e ^--> qqbar事件的总速率的极限，乘以分支分数，比在这些事件中测得的粲λ c和粲σ c重子的速率低大约三个数量级。
The $p_{\rm T}$-differential inclusive production cross sections of the prompt charmed mesons $D^0$, $D^+$, and $D^{*+}$ in the rapidity range |y|<0.5 were measured in proton-proton collisions at $\sqrt{s} = 7$ TeV at the LHC using the ALICE detector. Reconstructing the decays $D^0\rightarrow K^-π^+$, $D^+\rightarrow K^-π^+π^+$, $D^{*+}\rightarrow D^0π^+$, and their charge conjugates, about 8,400 $D^0$, 2,900 $D^+$, and 2,600 $D^{*+}$ mesons with 1<$p_{\rm T}$<24 GeV/$c$ were counted, after selection cuts, in a data sample of 3.14x10$^8$ events collected with a minimum-bias trigger (integrated…
During run I, the LHCb experiment at the LHC, CERN, collected 1.0 fb$^{-1}$ of pp collisions at $\sqrt{s} = 7$ TeV and 2.0 fb$^{-1}$ at $\sqrt{s} = 8$ TeV, yielding the world's largest sample of decays of charmed hadrons. This sample is used to search for direct and indirect CP violation in charm and to measure $D^{0}$ mixing parameters. Recent measurements from several complementary decay modes are presented.
The production cross sections for prompt open-charm mesons in proton-proton collisions at a center-of-mass energy of 13 TeV are reported. The measurement is performed using a data sample collected by the CMS experiment corresponding to an integrated luminosity of 29 nb$^{-1}$. The differential production cross sections of the D$^{*\pm}$, D$^\pm$, and D$^0$ ($\overline{\mathrm{D}}^{0}$) mesons are presented in ranges of transverse momentum and pseudorapidity 4 $\lt$ $p_\mathrm{T}$ $\lt$ 100 GeV and $\lvertη\rvert$ $\lt$ 2.1, respectively. The results are compared to several theoretical calculat…
In this article, we report on the STAR results of open charm hadron production at mid-rapidity in $p+p$ and Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV and $p+p$ collisions at $\sqrt{s}$ = 500 GeV. The measurements cover transverse momentum range from 0.6 to 6 GeV/c for $p+p$ 200 GeV collisions, from 1 to 6 GeV/c for $p+p$ 500 GeV collisions and from 0 to 6 GeV/c for Au+Au 200 GeV collisions. $D^0$ nuclear modification factor and elliptic flow in Au+Au collisions at $\sqrt{s_{NN}}$ = 200 GeV are presented.
Multiparticle azimuthal correlations of prompt D$^0$ mesons are measured in PbPb collisions at a nucleon-nucleon center-of-mass energy of $\sqrt{s_\mathrm{NN}} =$ 5.02 TeV. For the first time, a four-particle cumulant method is used to extract the second Fourier coefficient of the azimuthal distribution ($v_2$) of D$^0$ mesons as a function of event centrality and the D$^0$ transverse momentum. The ratios of the four-particle $v_2$ values to previously measured two-particle cumulant results provide direct experimental access to event-by-event fluctuations of charm quark azimuthal anisotropies.…
The production of a W boson in association with a single charm quark is studied using 4.6 fb^-1 of pp collision data at sqrt(s)=7 TeV collected with the ATLAS detector at the Large Hadron Collider. In events in which a W boson decays to an electron or muon, the charm quark is tagged either by its semileptonic decay to a muon or by the presence of a charmed meson. The integrated and differential cross sections as a function of the pseudorapidity of the lepton from the W-boson decay are measured. Results are compared to the predictions of next-to-leading-order QCD calculations obtained from vari…
The results of data handling for E-184 experiment obtained with 70 GeV proton beam irradiation of active target with carbon, silicon and lead plates are presented. Two-prongs neutral charmed D0 and Ď0 -mesons decays were selected. Signal / background ratio was (51+/-17) / (38+/-13). Registration efficiency for mesons was defined and evaluation for charm production cross section at threshold energy is presented: sigma(cĉ) = 7.1 +/- 2.4(stat.) +/- 1.4(syst.) (μ/nucleon).
I report BESIII preliminary results on: 1 Measurement of sigma(e+e- ->DDbar at Ecm = 3.773 GeV 2 Study of the DDbar production line shape near Ecm = 3.773 GeV 3 The first observation of singly Cabibbo-suppressed decay, D -> omega pi 4 Measurement of BF(Ds+ -> eta' X) and BF(Ds+ -> eta' rho+) .
Measurements are presented of differential cross sections for the production of Z bosons in association with at least one jet initiated by a charm quark in pp collisions at $\sqrt{s} =$ 13 TeV. The data recorded by the CMS experiment at the LHC correspond to an integrated luminosity of 35.9 fb$^{-1}$. The final states that contain a pair of electrons or muons that are the decay products of a Z boson, and a jet consistent with being initiated by a charm quark produced in the hard interaction. Differential cross sections as a function of the $p_\mathrm{T}$ of the Z boson and $p_\mathrm{T}$ of th…
The CMS Collaboration presents the first measurement of the differential cross section of jets from charm quarks produced in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass energy of sqrt(s[NN]) = 5.02 TeV, as well as results from charm quark jets in proton-proton (pp) collisions at sqrt(s) = 2.76 and 5.02 TeV. By comparing the yields of the pPb and pp collision systems at the same energy, a nuclear modification factor for charm jets from 55 to 400 GeV/c in pPb collisions at sqrt(s[NN]) = 5.02 TeV of R[pA] = 0.92 +/- 0.07 (stat) +/- 0.11 (syst) is obtained. This is consistent …
Measurements of cross sections for beauty and charm events with dijets and a muon in the photoproduction regime at HERA are presented. The data were collected with the H1 detector and correspond to an integrated luminosity of 179 pb^{-1}. Events with dijets of transverse momentum P_T^{jet1} > 7 GeV and P_T^{jet2} > 6 GeV in the pseudorapidity range -1.5< η^{jet} < 2.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q^2 < 2.5 GeV^2 and inelasticity 0.2 < y < 0.8. One of the two selected jets must be associated to a muon with P_T^μ > 2.5 GeV in the pseudorapidit…
The BESIII experiment has collected the $e^+e^-$ collision data samples corresponding to integrated luminosities of 2.93 $\mathrm{fb}^{-1}$, $3.19$ $\mathrm{fb}^{-1}$, 3.13 $\mathrm{fb}^{-1}$ and 567 $\mathrm{pb}^{-1}$ at center-of-mass energies of 3.773 GeV, 4.178 GeV, 4.189-4.226 GeV and 4.599 GeV, respectively. We report the measurements of strong-phase parameters based on the decays $D^0\to K^0_{S/L}π^+π^-$, $D^0\to K^0_{S/L}K^+K^-$, $D^0\to K^-π^+π^+π^-$ and $D^0\to K^-π^+π^0$, which are important input for binned model-independent measurement of the CKM angle $γ/ϕ_3$. In addition, we rep…
Measurements of the associated production of a W boson and a charm (c) quark in proton-proton collisions at a centre-of-mass energy of 8 TeV are reported. The analysis uses a data sample corresponding to a total integrated luminosity of 19.7 fb$^{-1}$ collected by the CMS detector at the LHC. The W bosons are identified through their leptonic decays to an electron or a muon, and a neutrino. Charm quark jets are selected using distinctive signatures of charm hadron decays. The product of the cross section and branching fraction $σ$(pp $\to$ W + c + X) $\mathcal{B}$(W $\to$ $\ellν$), where $\ell…
A search for supersymmetric partners of top quarks decaying as $\tilde{t}_1\to c\tildeχ^0_1$ and supersymmetric partners of charm quarks decaying as $\tilde{c}_1\to c\tildeχ^0_1$, where $\tildeχ^0_1$ is the lightest neutralino, is presented. The search uses 36.1 ${\rm fb}^{-1}$ $pp$ collision data at a centre-of-mass energy of 13 TeV collected by the ATLAS experiment at the Large Hadron Collider and is performed in final states with jets identified as containing charm hadrons. Assuming a 100% branching ratio to $c\tildeχ^0_1$, top and charm squarks with masses up to 850 GeV are excluded at 95%…
We report on the measurements of production of various charmed hadrons in Au+Au collisions at $\sqrt{s_{\rm{NN}}}$ = 200 GeV (including $D^{0}(\overline{D^{0}})$ and $Λ_{c}^{\pm}$) obtained via topological reconstruction, utilizing the Heavy Flavor Tracker at STAR. Precise results on the $D^{0}$ yields from the 2014 data are reported for a wide transverse momentum range down to 0 in various centrality bins. With the high-statistics data collected in 2014 and 2016, and the usage of a supervised machine learning algorithm for signal-to-background separation, the first measurement of the centrali…
The results of the SERP-E-184 experiment at the U-70 accelerator (IHEP, Protvino) are presented. Interactions of the 70 GeV proton beam with carbon, silicon and lead targets were studied to detect decays of charmed $D^0$, $\bar D^0$, $D^+$, $D^-$ mesons and $Λ_c^+$ baryon near their production threshold. Measurements of lifetimes and masses have shown a good agreement with PDG data. The inclusive cross sections of charm production and their A-dependencies have been obtained. The yields of these particles are compared with the theoretical predictions and the data of other experiments. The measu…
Results are presented from a search for the pair production of third-generation squarks in proton-proton collision events with two-body decays to bottom or charm quarks and a neutralino, which produces a significant imbalance in the transverse momentum. The search is performed using a sample of proton-proton collision data at sqrt(s) = 13 TeV recorded by the CMS experiment at the LHC, corresponding to an integrated luminosity of 35.9 inverse femtobarns. No statistically significant excess of events is observed beyond the expected contribution from standard model processes. Exclusion limits are…
Measurements of cross sections for events with charm and beauty jets in deep inelastic scattering at HERA are presented. Events with jets of transverse energy E_T^jet > 6 GeV and pseudorapidity -1.0 < eta^jet < 1.5 in the laboratory frame are selected in the kinematic region of photon virtuality Q^2 > 6 GeV^2 and inelasticity variable 0.07 < y < 0.625. Measurements are also made requiring a jet in the Breit frame with E_T^*jet > 6 GeV. The data were collected with the H1 detector in the years 2006 and 2007 corresponding to an integrated luminosity of 189 pb^-1. The numbers of charm and beauty …
Measurements are presented of associated production of a W boson and a charm quark (W+c) in proton-proton collisions at a center-of-mass energy of 13 TeV. The data correspond to an integrated luminosity of 35.7 fb$^{-1}$ collected by the CMS experiment at the CERN LHC. The W bosons are identified by their decay into a muon and a neutrino. The charm quarks are tagged via the full reconstruction of D$^*$(2010)$^\pm$ mesons that decay via D$^*$(2010)$^\pm \to$ D$^0$ + $π^\pm \to$ K$^{\mp}$ + $π^\pm$ + $π^\pm$. A cross section is measured in the fiducial region defined by the muon transverse momen…
