We consider the production of charmed baryons and mesons in the proton-antiproton binary reactions at the energies of the future $\bar{P}$ANDA experiment. To describe these processes in terms of hadronic interaction models, one needs strong couplings of the initial nucleons with the intermediate and final charmed hadrons. Similar couplings enter the models of binary reactions with strange hadrons. For both charmed and strange hadrons we employ the strong couplings and their ratios calculated from QCD light-cone sum rules. In this method finite masses of $c$ and $s$ quarks are taken into account. Employing the Kaidalov's quark-gluon string model with Regge poles and adjusting the normalization of the amplitudes in this model to the calculated strong couplings, we estimate the production cross section of charmed hadrons. For $p\bar{p}\to Λ_c\barΛ_c$ it can reach several tens of $nb$ at $p_{lab}= 15 {GeV}$, whereas the cross sections of $Σ_c$ and $D$ pair production are predicted to be smaller.
Charm and charmonium physics have gained renewed interest in the past decade. Recent spectroscopic observations strongly motivate these studies. Among the several possible reactions, measurements in proton-antiproton annihilation play an important role, complementary to the studies performed at B-factories. The fixed target PANDA experiment at FAIR (Darmstadt, Germany) will investigate fundamental questions of hadron and nuclear physics in the interactions of antiprotons with nucleons and nuclei. With reaction rates as large as 2*10^7 interactions/s, and a mass resolution 20 times better as co…
Charmonium production in association with a forward or backward pion in nucleon-antinucleon annihilation is one of the most promising reaction to access nucleon-to-pion transition distribution amplitudes (TDAs) at PANDA. We briefly review the description of this reaction in terms of πN TDAs within the collinear factorization approach and present the first results of dedicated feasibility studies for the PANDA experimental setup.
In this work we evaluate the production rate of the charmed baryon $Λ_c(2940)^+$ at PANDA. For possible assignments of $Λ_c(2940)^+$: $J^P=1/2^\pm$, $3/2^\pm$ and $5/2^\pm$, the total cross section of $p\bar{p}\to \barΛ_c Λ_c(2940)^+$ is estimated, which may exceed 1 nb. With the designed luminosity ($2\times10^{-32}$cm$^{-2}$/s) of PANDA, our estimate indicates that ten thousand events per day if $Λ_c(2940)^+$ is of $J^P=1/2^+$ or $10^8$ per day if it is of $J^P=5/2^+$ can be expected. Those values actually set the lower and upper limits of the $Λ_c(2940)^+$ production. In addition, we presen…
In the present work we explore the production potential of $Λ_c(2880)^+$ at PANDA. With the $J^P=\frac{5}{2}^+$ assignment to $Λ_c(2880)^+$, we calculate the differential and total cross sections of $p\bar{p}\to Λ_c^-Λ_c(2880)^+$. We also perform the Dalitz plot analysis and give the $pD^0$ invariant mass spectrum distribution of the process $p\bar{p}\to Λ_c^-pD^0$, where the signal and background contributions are considered. Our numerical results indicate that the production of $Λ_c(2880)^+$ may reach up to about 20 $μ$b. About $10^7$ events from the reconstruction of $pD^0$ can be accumulat…
The production of the charmonium states in proton-antiproton experiments is considered at the energy rates near threshold in NLO. Such a consideration allows one to obtain non zero distributions over the transverse momentum of the final charmonium and gives a natural explanation to the existence of $χ_{c1}$-meson in final state, that is observed experimentally and cannot be produced in leading order processes. The crucial role of scale parameter choice in $α_s (Q^2)$ and partonic distributions $f(x,Q^2)$ shown, and the correct choice offered.
The $\bar PANDA$ experiment at FAIR (Facility for Antiproton and Ion Research) in Darmstadt (Germany) is designed for $\bar p p$ annihilation studies and it will investigate fundamental questions of hadron and nuclear physics in interactions of antiprotons with nucleons and nuclei. Gluonic excitations and the physics of hadrons with strange and charm quarks will be accessible with unprecedented accuracy, thereby allowing high precision tests of the strong interactions. In particular, the $D_{s0}^*(2317)^+$ and $D_{s1}(2460)^+$ are still of high interest 11 years after their discovery, because …
In this work, we calculate the total cross sections and the center-of-mass frame angular distributions of the charmonium production plus a light meson by the low energy $p\bar{p}$ interaction. The results of $p\bar{p}\to π^0 Ψ$ with and without form factor (FF) indicate that the FF contribution in the calculation cannot be ignored. The obtained cross section of $p\bar{p}\to π^0 J/ψ$ with FF can fit the E760 data well. We also predict the total cross sections and the center-of-mass frame angular distributions of $p\bar{p}\to ωΨ$, which show that these physical quantities are dependent on Pauli …
We study the production of $Z^\pm(4430)$ at a nucleon-antinucleon scattering experiment. Considering the PANDA experiment to be an ideal platform to explore the production of the charmonium and charmonim-like states, we suggest the forthcoming PANDA experiment to pay attention to the production of $Z^\pm(4430)$.
The PANDA detector at FAIR aims to conduct an antiproton-proton experiment with a very high rate capability. It is expected to feature high mass resolution, more than 20 times better than achieved at B-factories. PANDA is in a unique position to perform highly resolved mass scan, and to measure the width of very narrow charm and charmonium-like states, whose nature is still unknown, 12 years after their discovery. In this report, we present a method to determine the width of the $D_{s0}^*(2317)^+$. We discuss the future perspectives of PANDA, based on our present simulations, in relation with …
The QCD mechanisms underlying the exclusive strong decays and hadronic production amplitudes of charmonium remain poorly understood, despite decades of study and an increasingly detaled body of experimental information. One set of hadronic channels of special interest are those that include baryon-antibaryon states. These are being investigated experimentally at BES and CLEO-c in terms of their baryon resonance content, and are also of interest for the future PANDA experiment, in which charmonium and charmonium hybrids will be produced in p-pbar annihilation in association with light mesons. I…
Exciting new scientific opportunities are presented for the PANDA detector at the High Energy Storage Ring in the redefined $\bar{\text{p}} \text{p}(A)$ collider mode, HESR-C, at the Facility for Antiproton and Ion Research (FAIR) in Europe. The high luminosity, $L \sim 10^{31}$ cm$^{-2}$ s$^{-1}$, and a wide range of intermediate and high energies, $\sqrt{s_{\text{NN}}}$ up to 30 GeV for $\bar{\text{p}} \text{p}(A)$ collisions will allow to explore a wide range of exciting topics in QCD, including the study of the production of excited open charm and bottom states, nuclear bound states contai…
Inspired by the present experimental status of charmed-strange mesons, we perform a systematic study of the charmed-strange meson family, in which we calculate the mass spectra of the charmed-strange meson family by taking a screening effect into account in the Godfrey-Isgur model and investigate the corresponding strong decays via the quark pair creation model. These phenomenological analyses of charmed-strange mesons not only shed light on the features of the observed charmed-strange states, but also provide important information on future experimental search for the missing higher radial an…
The interactions of $\bar{D}Σ_{c}$-$\bar DΛ_c$, $\bar{D}^{*}Σ_{c}$-$\bar D^*Λ_c$, and related strangeness channels, are studied within the framework of the coupled channel unitary approach with the local hidden gauge formalism. A series of meson-baryon dynamically generated relatively narrow $N^*$ and $Λ^*$ resonances are predicted around 4.3 GeV in the hidden charm sector. We make estimates of production cross sections of these predicted resonances in $\bar{p} p $ collisions for PANDA at the forthcoming FAIR facility.
The J/Ψ(1S) and Ψ'(2S) production near threshold in antiproton-nucleus reactions is calculated on the basis of the Glauber model. The model takes into account the antiproton (pre)absorption, proton Fermi motion, and charmonium formation length. We confirm earlier prediction that the charmonium production in $\bar pA$ collisions at $p_{lab}=3-10$ GeV/c is not influenced by formation length effects and is very well suited to determine the genuine charmonium-nucleon dissociation cross sections. The comparison is performed with the J/Ψphotoproduction at high energies, where formation length effect…
The recently discovered $X$(3872) has many possible interpretations. We study the production of $X$(3872) with PANDA at GSI for the antiproton-proton collision with two possible interpretations of X(3872). One is as a loosely-bound molecule of $D$-mesons, while another is a 2P charmonium state $χ_{c1}$ (2P). Using effective couplings we are able to give numerical predictions for the production near the threshold and the production associated with $π^0$. The produced $X$(3872) can be identified with its decay $J/ψπ^+π^-$. We also study the possible background near the threshold production for $…
Exciting new scientific opportunities are presented for the PANDA detector at the High Energy Storage Ring in the redefined $\overline{\text{p}} \text{p}(A)$ collider mode, HESR-C, at the Facility for Antiproton and Ion Research (FAIR) in Europe. The high luminosity, $L \sim 10^{31}$ cm$^{-2}$ s$^{-1}$, and a wide range of intermediate and high energies, $\sqrt{s_{\text{NN}}}$ up to 30 GeV for $\overline{\text{p}} \text{p}(A)$ collisions will allow to explore a wide range of exciting topics in QCD, including the study of the production of excited open charm and bottom states, nuclear bound sta…
On the basis of the generalized eikonal approximation we study the exclusive reactions $\bar p d \to J/ψ\, n$ and $\bar p d \to ψ^\prime\, n$ in vicinity of the thresholds for charmonium production on a free proton target. It is shown that the rescattering of the incoming antiproton and outgoing charmonium on the spectator neutron leads to a depletion of the charmonium production at low- and to an enhancement at high transverse momenta. This is in qualitative agreement with previous studies of hard proton knockout in proton-deuteron collisions. We analyze different physical sources of uncertai…
We investigate the structure and formation of charmed meson--nucleus systems, with the aim of understanding the charmed meson--nucleon interactions and the properties of the charmed mesons in the nuclear medium. The $\bar{D}$ mesic nuclei are of special interest, since they have tiny decay widths due to the absence of strong decays for the $\bar{D} N$ pair. Employing an effective model for the $\bar{D} N$ and $D N$ interactions and solving the Klein--Gordon equation for $\bar{D}$ and $D$ in finite nuclei, we find that the $D^{-}$-${}^{11}\rm{B}$ system has $1 s$ and $2p$ mesic nuclear states a…
In this work, we study the reaction of a nucleon and a doubly charmed state $T_{cc}$. Under the assumption of the $T_{cc}$ as a molecular state of $D^{*}D$, the reaction of the nucleon and $T_{cc}$ is mediated by exchanges of $π$, $η$, $ρ$, and $ω$ meson, which results in split of $T_{cc}$ state with two $D$ mesons in final state. With the help of the effective Lagrangians, the cross section of $p+T^+_{cc}\to p+D^++D^0$ process is calculated, and a very large cross section can be obtained with very small incoming momentum of proton. It decrease rapidly with the increase of the momentum to abou…
Starting from the Feynman diagram representation of multiple scattering we consider the polarized $χ_c$(1P)-charmonia production in antiproton-nucleus reactions close to the threshold ($p_{\rm lab}=5-7$ GeV/c). The rescattering and absorption of the incoming antiproton and outgoing charmonium on nucleons are taken into account, including the possibility of the elastic and nondiagonal (flavor-conserving) scattering $χ_{cJ} N \to χ_{cJ^\prime} N$, $J,J^\prime=0,1,2$. The elementary amplitudes of the latter processes are evaluated by expanding the physical $χ_c$-states in the Clebsch-Gordan serie…
There must be Coulomb bound states of a pair of hadrons, which are stable against the strong interaction, with opposite electric charges. Such bound states are hadronic atoms. We study the properties and the production of the ground-state $D^+D^-$ hadronic atom $A_{D^+D^-}$, called dionium, with quantum numbers $J^{PC}=0^{++}$. Using a nonrelativistic effective field theory for the $D^0\bar{D}^0$-$D^+D^-$ coupled-channel system, the mass of the ground-state dionium is predicted to be $(3739.3 \pm 0.1)~\text{MeV}$, with the binding energy reduced by about 10% compared to the Coulomb binding ene…
We investigate the charmed baryon production reaction $p\bar{p}\rightarrowΛ_c\barΛ_c$ in an effective Lagrangian approach. Besides the $t$-channel $D^0$ and $D^{*0}$ mesons exchanges, the $s$-channel $Y(4630)$ meson exchange is taken into account. For the total cross sections, the $D^0$ and $D^{*0}$ mesons provide minor background contributions, while the $Y(4630)$ state gives a clear peak structure with the magnitude of 10 $μ$b at center of mass energy 4.63 GeV. Basing on the results, we suggest that the reaction of $p\bar{p}\rightarrowΛ_c\barΛ_c$ can be used to search for the $1^{--}$ charmo…
We provide comprehensive investigations for the mass spectrum of exotic open-flavor charmed/bottom $sq\bar q\bar c$, $qq\bar q\bar c$, $sq\bar q\bar b$, $qq\bar q\bar b$ tetraquark states with various spin-parity assignments $J^P=0^+, 1^+, 2^+$ and $0^-, 1^-$ in the framework of QCD sum rules. In the diquark configuration, we construct the diquark-antidiquark interpolating tetraquark currents using the color-antisymmetric scalar and axial-vector diquark fields. The stable mass sum rules are established in reasonable parameter working ranges, which are used to give reliable mass predictions for…
We discuss charm production at LHC. The production of single $c \bar c$ pairs is calculated in the $k_t$-factorization approach. We use several unintegrated gluon distributions from the literature. The hadronization is included with the help of fragmentation functions found for the production of charmed mesons in $e^+ e^-$ collisions. Differential distributions for several charmed mesons are presented and compared to recent results of the ALICE and LHCb collaborations. Furthermore we discuss production of two pairs of $c \bar c$ within a simple formalism of double-parton scattering (DPS). Surp…
We calculate and resum the nuclear enhanced power corrections from the final state partonic scattering in nuclear matter to open charm production and correlations. In p+A reactions, we find that single and double inclusive D mesons can be suppressed as much as the neutral pions from the dynamical high twist shadowing. Effects of initial state energy loss in p+A collisions are also investigated and may lead to significantly weaker transverse momentum dependence of the nuclear suppression.
This reports our recent studies on changes in properties of heavy hadrons containing at least a charm or a bottom quark in nuclear matter, and that the results for the $Λ^+_c$ and $Λ_b$ hypernuclei are studied quantitatively. Comparisons are made with the results for the $Λ$ hypernuclei studied previously in the same approach. It is shown that although the scalar and vector potentials for the $Λ$, $Λ_c^+$ and $Λ_b$ in the hypernuclei multiplet with the same baryon numbers are quite similar, the wave functions obtained, e.g., for $1s_{1/2}$ state, are very different. The $Λ^+_c$ probability den…
We discuss charm production at the LHC. The production of single $c \bar c$ pairs is calculated in the $k_t$-factorization approach. We use Kimber-Martin-Ryskin unintegrated gluon distributions in the proton. The hadronization is included with the help of Peterson fragmentation functions. Transverse momentum and pseudorapidity distributions of charmed mesons are presented and compared to recent results of the ALICE, LHCb and ATLAS collaborations. Furthermore we discuss production of two pairs of $c \bar c$ within a simple formalism of double-parton scattering (DPS). Surprisingly large cross se…
The LHCb Collaboration at the Large Hadron Collider at CERN discovered two pentaquark states $P_c(4380)$ and $P_c(4450)$. These two hidden-charm states are interpreted as the loosely bound $Σ_c(2455)D^*$ and $Σ_c^*(2520)D^*$ molecular states in the boson exchange interaction model, which provides an explanation for why the experimental width of $P_c(4450)$ is much narrower than that of $P_c(4380)$. The discovery of the new resonances $P_c(4380)$ and $P_c(4450)$, indeed, opens a new page for hadron physics. The partners of $P_c(4380)$ and $P_c(4450)$ should be pursued in future experiments.
We investigate the possibility that scalar leptoquarks generate consequential effects on the flavor-changing neutral-current decays of charmed hadrons into final states with missing energy ($\not\!\!E$) carried away by either standard model or sterile neutrinos. We focus on scenarios involving the $R_2$, $\tilde R_2$, and $\bar S_1$ leptoquarks and take into account various pertinent constraints, learning that meson-mixing ones and those inferred from collider searches can be of significance. We find in particular that the branching fractions of charmed meson decays $D\to M\!\not\!\!E$, $M=π,ρ…
In recent studies of inclusive $B$ decays, it has been suggested that either $B$ mesons decay much more copiously to final states with no open charm than currently assumed, or $B(D^0 \to K^-π^+)$ has to be reduced significantly. This note takes the experimental $B(D^0 \to K^-π^+)$ at its face value and estimates $B(b\to$ no open charm) using complementary methods: one accounts for the $c$ quark in $b\to c$ transitions, the other accounts for the $\bar c$ quark in $b\to c\bar c s$ transitions. Through cancellation of errors, the average gives our best estimate of $B(b\to$ no open charm), and th…
Recent measurements of various charm-hadron ratios in $pp$, $p$-Pb and Pb-Pb collisions at the LHC have posed challenges to the theoretical understanding of heavy-quark hadronization. The $Λ_c/D^0$ ratio in $pp$ and $p$-Pb collisions shows larger values than those found in $e^+e^-$ and $ep$ collisions and predicted by Monte-Carlo event generators based on string fragmentation, at both low and intermediate transverse momenta ($p_T$). In AA collisions, the $D_s/D$ ratio is significantly enhanced over its values in $pp$, while the $Λ_c/D^0$ data indicates a further enhancement at intermediate $p_…
We revisit the calculation of charm particle production in hadron collisions, focusing on the production of charm particles that carry a large fraction of the momentum of the incident proton. In the case of strange particles, such a component is familiar from the abundant production of $K^+Λ$ pairs. Modern collider experiments have no coverage in the very large rapidity region where the forward pair production dominates. While forward charm particles are produced inside the LHC beampipe, they dominate the high-energy atmospheric neutrino flux in underground experiments because long-lived pions…
The couplings of charmonia and charmonium hybrids (generically Psi) to ppbar are of great interest in view of future plans to study these states using an antiproton storage ring at GSI. These low to moderate energy Psi-ppbar couplings are not well understood theoretically, and currently must be determined from experiment. In this letter we note that the two independent Dirac (gamma_mu) and Pauli (sigma_munu) ppbar couplings of the J/psi and psi' can be constrained by the angular distribution of e+e- -> (J/psi, psi') -> ppbar on resonance. A comparison of our theoretical results to recent unpol…
This dissertation presents a theoretical study of soft hadron production in relativistic heavy-ion collisions. We explore the principles governing the hadronization of the expanding QGP fireball, and to understand its properties. Much of the ongoing effort is to demonstrate the validity of a QGP hadronization model which describes the particle production data accurately. We begin with a centrality study of multistrange hadrons from Au-Au collisions at 62.4 GeV at RHIC. We show that the statistical hadronization model (SHM) well describes particle production in QGP hadronization. For all centra…
We investigate the charmless decays of excited $P$-wave charmonia $χ_{c1}^\prime \to VV$ and $χ_{c2}^\prime \to VP$ via intermediate charmed meson loops, where $V$ and $P$ denote the light vector and pseudoscalar mesons, respectively. Within the model parameters, the charmed meson loop contributions are evaluated by using the effective Lagrangian approach. For $χ_{c1}^\prime \to VV$, the partial widths of the $ρρ$, $ωω$, and $K^*{\bar K}^*$ channels can reach to the order of MeV, while the partial width of the $ϕϕ$ channel is very small and in the order of keV. For $χ_{c2}^\prime \to V P$, the…
The recent observation of $D^0 - \bar D^0$ oscillations has left us in a quandary concerning the theoretical interpretation: are they driven by SM forces alone or do they involve new dynamics? A comprehensive analysis of \cp symmetry in $D$ decays can probably resolve the issue. Charm studies might thus haul in their biggest prize yet: clear evidence for the intervention of New Physics. While the absolute size of \cp asymmetries will presumably be modest at best, SM contributions should be much smaller still. Thus the ratio of `signal' to `noise' -- i.e. NP over SM contributions -- might well …
Charm production gives rise to a flux of very high energy neutrinos from astrophysical sources with jets driven by central engines, such as gamma ray bursts or supernovae with jets. The neutrino flux from semi-leptonic decays of charmed mesons is subject to much less hadronic and radiative cooling than the conventional flux from pion and kaon decays and therefore has a dominant contribution at higher energies, of relevance to future ultrahigh energy neutrino experiments.
Charmed nuclei and exotic charmed meson production at CBM@FAIR and ALICE@LHC
Suranaree University of Technology（素叻他尼理工大学）；GSI Helmholtzzentrum für Schwerionenforschung GmbH（GSI亥姆霍兹重离子研究中心有限公司）；Frankfurt Institute for Advanced Studies（法兰克福高级研究所）；Institut für Kernphysik, Goethe-Universität Frankfurt（法兰克福歌德大学核物理研究所）；Theoretical Physics Department, CERN（欧洲核子研究中心理论物理部）；Department of Physics, University of Houston（休斯顿大学物理系）
We have discussed single and central diffractive production of $c \bar c$ pairs in the Ingelman-Schlein model. In these calculations we have included diffractive parton distributions obtained by the H1 collaboration at HERA and absorption effects neglected in some early calculations in the literature. The absorption effects which are responsible for the naive Regge factorization breaking cause that the cross section for diffractive processes is much smaller than that for the fully inclusive case, but could be measured at RHIC and LHC by imposing special condition on rapidity gaps. We discuss a…
We discuss the role of intrinsic charm (IC) in the nucleon for forward production of $c$-quark (or $\bar c$-antiquark) in proton-proton collisions for low and high energies. The calculations are performed in collinear-factorization approach with on-shell partons, $k_T$-factorization approach with off-shell partons as well as in a hybrid approach using collinear charm distributions and unintegrated (transverse momentum dependent) gluon distributions. For the collinear-factorization approach we use matrix elements for both massless and massive charm quarks/antiquarks. The distributions in rapidi…
Inspired by the observation of the fully-charm tetraquark $X(6900)$ state at LHCb, the production of $X(6900)$ in $\bar{p}p\rightarrow J/ψJ/ψ$ reaction is studied within an effective Lagrangian approach and Breit-Wigner formula. The numerical results show that the cross section of $X(6900)$ at the c.m. energy of 6.9 GeV is much larger than that from the background contribution. Moreover, we estimate dozens of signal events can be detected by D0 experiment, which indicates that searching for the $X(6900)$ via antiproton-proton scattering may be a very important and promising way. Therefore, rel…
We study the relative contribution of partonic sub-processes to D meson production and D meson-triggered inclusive di-hadrons to lowest order in perturbative QCD. While gluon fusion dominates the creation of large angle DD-bar pairs, charm on light parton scattering determines the yield of single inclusive D mesons. The distinctly different non-perturbative fragmentation of c quarks into D mesons versus the fragmentation of quarks and gluons into light hadrons results in a strong transverse momentum dependence of anticharm content of the away-side charm-triggered jet. In p+A reactions, we calc…
The flavor changing neutral current tcV (V=γ,Z) couplings in the production vertex for the process $e^+e^-\to t\bar c$ or $\bar t c$ in the standard model are investigated. The precise calculations keeping all quark masses non-zero are carried out. The total production cross section is found to be $1.84 \times 10^{-9}$ fb at $\sqrt s =200 GeV$ and $0.572 \times 10^{-9}$ fb at $\sqrt s =500 GeV$ respectively. The result is much smaller than that given in ref. \cite{clwy} by a factor of $10^{-5}$.
QCD sum rules involving mixed inverse moment integration kernels are used in order to determine the running charm-quark mass in the $\bar{MS}$ scheme. Both the high and the low energy expansion of the vector current correlator are involved in this determination. The optimal integration kernel turns out to be of the form $p(s) = 1 - (s_0/s)^2$, where $s_0$ is the onset of perturbative QCD. This kernel enhances the contribution of the well known narrow resonances, and reduces the impact of the data in the range $s \simeq 20 - 25 GeV^2$. This feature leads to a substantial reduction in the sensit…
We find a new $CP$ violating effect in charmed hadron decays into neutral kaons, which is induced by the interference between the Cabibbo-favored and doubly Cabibbo-suppressed amplitudes with the $K^{0}-\overline K^{0}$ mixing. It is estimated to be of order of $\mathcal{O}(10^{-3})$, much larger than the direct $CP$ asymmetry, but missed in the literature. To reveal this new $CP$ violation effect, we propose a new observable, the difference of the $CP$ asymmetries in the $D^{+}\to π^{+}K_S^0$ and $D_{s}^{+}\to K^{+} K_S^0$ modes. Once the new effect is determined by experiments, the direct $C…
We give the explicit wave functions of the $qqqq\bar{q}$ components of the C=+1, J=1/2 charmed baryons, $Σ_{c}$, $Λ_{c}$ and $Ξ_{c}^{a}$, and calculate the magnetic moments by adding the 5q components contributions, and we also compute the magnetic moments of the $Σ_{b}$ and $Σ_{b}^{*}$ baryons. The influence of the additional light and strange $q\bar{q}$ pairs is investigated. It's obvious that the constituent quark masses of the charm and beauty quarks are much heavier than that of the light and strange quarks, consequently, the hidden flavor contributions to the baryons magnetic moments may…
We consider an observable very sensitive to the non-zero intrinsic charm (IC) contribution to the proton density. It is the ratio between the differential cross sections of the photon or $Z$-boson and $c$-jet production in the $pp$ collision, $γ(Z) + c$, and the $γ(Z)$ and the $b$-jet production. It is shown that this ratio can be approximately flat or increasing at large $γ(Z)$ transverse momenta $p_T$ and their pseudo-rapidities $1.5 < η< 2.4$ if the IC contribution is taken into account. On the contrary, in the absence of the IC this ratio decreases as $p_T$ grows. We also present the ratio…
Our community has to apply {\em non}-perturbative QCD on different levels of flavor dynamics in strange, charm \& beauty hadrons and even for top quarks. We need {\em consistent} parameterization of the CKM matrix and describe weak decays of beauty hadrons with {\em many-body} final states. It is crucial to use the {\em Wilsonian} OPE as much as possible and discuss "duality" in the worlds of quarks and hadrons. The pole mass of heavy quarks is {\em not} well-defined on the {\em non}-perturbative level -- i.e., it is {\em not} Borel summable in total QCD. We need a novel team to combine the st…
Charmed mesons may be produced when a primary cosmic ray or the leading hadron in an air shower collide with an atmospheric nucleon. At energies \ge 10^8 GeV their decay length becomes larger than 10 km, which implies that they tend to interact in the air instead of decaying. We study the collisions of long-lived charmed hadrons in the atmosphere. We show that (Λ_c,D)-proton diffractive processes and partonic collisions of any q^2 where the charm quark is an spectator have lower inelasticity than (p,π)-proton collisions. In particular, we find that a D meson deposits in each interaction just a…
The top-charm associated productions via $e^+ e^-$, $e^- γ$ and $γγ$ collisions at linear colliders, which are extremely suppressed in the Standard Model (SM), could be significantly enhanced in some extensions of the SM. In this article we calculate the full contribution of the topcolor-assisted technicolor (TC2) to these productions and then compare the results with the existing predictions of the SM, the general two-Higgs-doublet model and the Minimal Supersymmetric Model. We find that the TC2 model predicts much larger production rates than other models and the largest-rate channel is $γγ\…
In this article, we investigate the $\bar{D}Σ_c$, $\bar{D}Ξ^\prime_c$, $\bar{D}Σ_c^*$, $\bar{D}Ξ_c^*$, $\bar{D}^{*}Σ_c$, $\bar{D}^{*}Ξ^\prime_c$, $\bar{D}^{*}Σ_c^*$ and $\bar{D}^{*}Ξ_c^*$ pentaquark molecular states with strangeness and without strangeness via the QCD sum rules at length, pay much attention to the light flavor $SU(3)$ breaking effects, and make predictions for new pentaquark molecular states besides assigning the $P_c(4312)$, $P_c(4380)$, $P_c(4440)$, $P_c(4457)$ and $P_{cs}(4459)$ self-consistently. We can search for those pentaquark molecular states in the decays of the $Λ_b…
We investigate the thermalization of charm quarks in high energy heavy ion collisions. To this end, we calculate the diffusion coefficient in the perturbative Quark Gluon Plasma and relate it to collisional energy loss and momentum broadening. We then use these transport properties to formulate a Langevin model for the evolution of the heavy quark spectrum in the hot medium. The model is strictly valid in the non-relativistic limit and for all velocities $γv < \alphas^{-1/2}$ to leading logarithm in $T/m_D$. The corresponding Fokker-Planck equation can be solved analytically for a Bjorken expa…
