Ds Mesons Research Articles

Kinetic energy and speed powers vn of a heavy quark inside S wave and P wave heavy-light mesons

The average values of the powers of |q→|n¯≡qn and |v→|n¯≡vn are commonly used physical quantities, where q→ and v→ are the three-dimensional momentum and velocity of a quark inside a meson, respectively. For example, the average kinetic energy μπ2=q2 is an important quantity in the heavy quark effective theory, and the expansion of vn is commonly used in the nonrelativistic quantum chromodynamics. In this paper, based on the instantaneous Bethe-Salpeter equation method, we calculate the average values qn and vn (n=1, 2, 3, 4) of a heavy quark inside S wave and P wave heavy-light mesons. We obtain the kinetic energy μπ2=0.455 GeV2 for the B meson, which is consistent with the experimental result 0.464±0.076 GeV2. For the Bs, D, and Ds mesons, the μπ2 are 0.530, 0.317, and 0.369 GeV2, respectively, and v2=0.0185, 0.0215, 0.121, and 0.140 for B, Bs, D, and Ds, respectively. We obtain some relationships, for example, q0−n(mS)≈q1−n(mS), q0+n(mP)≈q1+′n(mP′)>q1+n(mP)≈q2+n(mP), and qn(mS)<qn(mP) (m=1, 2, 3), etc. Published by the American Physical Society 2024

Puzzle of the cornell potential on the heavy and heavy-light meson spectra

We computed the eigenvalues and eigenfunctions via the Cornell potential, approximately, using Numerov approach. The experimental data for the quantum states 3 S 1 were utilized to fit the mass spectra. Results were compared with observed data and the results obtained from other potential functions in the existing literature for the heavy ( cc¯, bb¯ and bc¯ ) as well as heavy-light (B, Bs, D and Ds) meson states. The yielded meson spectra based on this potential are matching well with the available experimental data.

D and Ds decay constants in Nf = 2 + 1 QCD with Wilson fermions

We present results for the leptonic decay constants of the D and Ds mesons from Nf = 2 + 1 lattice QCD. We employ a set of 49 high statistics gauge ensembles generated by the Coordinated Lattice Simulations (CLS) effort utilising non-perturbatively improved Wilson fermions and the tree-level Symanzik improved gauge action at six values of the lattice spacing in the range a = 0.098 fm down to a = 0.039 fm, with pion masses varying from around 420 MeV down to below the physical point. The ensembles lie on three trajectories in the quark mass plane, two trajectories intersecting close to the physical quark mass point and the third one approaching the SU(3) chiral limit, enabling tight control of the light and strange quark mass dependence. We obtain fDs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {f}_{{\ extrm{D}}_{\ extrm{s}}} $$\\end{document} = 246.8(1.3) MeV, fD = 208.4(1.5) MeV and fDs\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$ {f}_{{\ extrm{D}}_{\ extrm{s}}} $$\\end{document}/fD = 1.1842(36), where the precision of our results is mostly limited by the determination of the scale.

The study of P-wave Ds mesons in coupled channel framework

We developed a coupled channel framework connecting the quark model and lattice QCD to systematically investigate the inner structures of the four lowest P-wave Ds states. The cs¯ core and D(⁎)K channels were considered. The possible coupling of cs¯ with the D(⁎)K channel and the channel-channel potentials were described by the quark-pair creation model and the light meson exchanging model, respectively. The lattice QCD data was treated as input by using the hamiltonian effective field theory. Our results showed that the physical Ds0⁎(2317) and Ds1⁎(2460) contain important bare cs¯ core and D(⁎)K component, while the Ds1⁎(2536) and Ds2⁎(2573) are almost the cs¯ mesons.

The Ds0(2590)+ as the dressed [formula omitted] meson in a coupled-channels calculation

The recent discovery of the Ds0(2590)+ meson by the LHCb Collaboration has stimulated the analysis of meson-meson channels effects in the two-body quark-antiquark meson spectrum. This resonance, assigned to the radial excitation of the pseudoscalar Ds+ meson, has a mass much lower than the predictions of naive quark models, which could indicate a non-negligible D(⁎)K(⁎) coupling which reduces its mass. Based on the importance of nearby meson-meson thresholds in the dynamics of P-wave Ds mesons such as the Ds0⁎(2317)+ and Ds1(2460)+, in this work we perform a coupled-channels calculation including the D(⁎)K(⁎), Ds(⁎)ω and Ds⁎η channels, and study the impact of incorporating those channels in the mass of the bare cs¯. The coupling between two and four-quark sectors is done by means of the P03 mechanism, with all the parameters constrained from previous studies of the heavy meson spectroscopy. The masses, widths and production line shapes of the resulting state are analyzed.

Impact of a thermal medium on D mesons and their chiral partners

We study D and Ds mesons at finite temperature using an effective field theory based on chiral and heavy-quark spin-flavor symmetries within the imaginary-time formalism. Interactions with the light degrees of freedom are unitarized via a Bethe-Salpeter approach, and the D and Ds self-energies are calculated self-consistently. We generate dynamically the D0⁎(2300) and Ds(2317) states, and study their possible identification as the chiral partners of the D and Ds ground states, respectively. We show the evolution of their masses and decay widths as functions of temperature, and provide an analysis of the chiral-symmetry restoration in the heavy-flavor sector below the transition temperature. In particular, we analyse the very special case of the D-meson, for which the chiral partner is associated to the double-pole structure of the D0⁎(2300).

DsTau: study of tau neutrino production with 400 GeV protons from the CERN-SPS

In the DsTau experiment at the CERN SPS (NA65), an independent and direct way to measure tau neutrino production following high energy proton interactions was proposed. As the main source of tau neutrinos is a decay of Ds mesons, produced in proton-nucleus interactions, the project aims at measuring a differential cross section of this reaction. The experimental method is based on a use of high resolution emulsion detectors for effective registration of events with short lived particle decays. Here we present the motivation of the study, details of the experimental technique, and the first results of the analysis of the data collected during test runs, which prove feasibility of the full scale study of the process in future.

HEAVY-LIGHT MESONS IN THE SYMMETRIES OF EXTENDED NONRELATIVISTIC QUARK MODEL

In present work, the modified Schrödinger equation (MSE) is analytically solved. The Heavy-Light Mesons (HLM) under modified nonrelativistic quark-antiquark potential, are extended to the symmetries of noncommutative quantum mechanics (NCQM), using the generalized Bopp’s shift method. The energy a spectrum of HLM has been investigated in the framework of the perturbative quantum chromodynamics (PQCD) extended nonrelativistic quark model. The new energy eigenvalues and the corresponding Hamiltonian operator are calculated in the 3-dimensional noncommutative real space phase (NC: 3D-RSP) symmetries. The masses of the scalar, vector, pseudoscalar, and pseudovector for (B, Bs , D and Ds) mesons have been calculated in (NC: 3D-RSP). Moreover, using the perturbation approach, we found that the perturbative solutions of discrete spectrum can be expressed by the parabolic cylinder functions function, Gamma function, the discreet atomic quantum numbers (j, l, s, m) of the ǪǬ state and (the spin independent and spin dependent) parameters (a, b, g, h), in addition to noncommutativity parameters. Furthermore, we have shown that the total complete degeneracy of new energy levels of HLM was changed to become equals to the new value 3n2 instead to the old values n2 in ordinary quantum mechanics. Our obtained results are in good agreement with the already existing literature in NCQM.

Study of tau neutrino production in proton-nucleus interactions

Tau neutrino properties are not so well known in comparison to those of muon or electron neutrinos. The tau neutrino interaction cross-section was directly measured by the DONUT experiment in 2008 on a basis of 9 registered tau neutrinos, and with a large systematical error of 50% due to a poor knowledge of the tau neutrino flux in this beam dump experiment. However, more accurate measurement of the cross section is needed for future neutrino experiments. It would also allow testing the Lepton Universality (LU) of Standard Model in neutrino interactions. Recently several results for B-meson decays (LHCb, Babar) demonstrated hints of possible LU violation. The tau neutrinos are produced in the Ds meson decays to tau, Ds → τ vT, and the cascade decay of the tau τ → vT X. DsTau experiment has been proposed to study the tau neutrino production at CERN SPS. It will measure the Ds production differential cross-section in the proton-tungsten interactions. This will allow reducing of the uncertainty due to the tau neutrino flux in the DONUT result from 50% to 10%. The peculiar Ds cascade decay topology ("double kink") in a few mm range will be detected by nuclear emulsion tracker thanks to its excellent spatial resolution (∼50nm).In 2016 and 2017, we made test beam exposures of nuclear emulsion modules at CERN SPS 400GeV/c proton beam followed by the pilot run in August 2018. A physics run in 2021 is scheduled. The status and prospects of the DsTau project as well as a review of the modern nuclear emulsion technique and the methods of its data analysis are presented.

Study of Tau Neutrino Production in Proton Nucleus Interactions

In the DsTau experiment at the CERN SPS, an independent direct way to study the tau neutrino production in high energy proton-nucleous interactions was proposed. Since the main source of tau neutrinos is a decay of Ds mesons, the project aims at measuring the differential cross-section of this reaction. The experimental method is based on the use of high-resolution emulsion detectors for the efficient registration of events with short-lived particle decays. The motivation of the project, details of the experimental technique, and the first results of the analysis of the data collected during test runs, which prove the feasibility of the study are presented.

Exclusive semileptonic decays of D and Ds mesons in the covariant confining quark model

Recently, the BESIII collaboration has reported numerous measurements of various D(s) meson semileptonic decays with significantly improved precision. Together with similar studies carried out at BABAR, Belle, and CLEO, new windows to a better understanding of weak and strong interactions in the charm sector have been opened. In light of new experimental data, we review the theoretical description and predictions for the semileptonic decays of D(s) to a pseudoscalar or a vector meson. This review is essentially an extended discussion of our recently published results obtained in the framework of the covariant confining quark model.

From [formula omitted] production asymmetry at the LHC to prompt ντ at IceCube

The description of the heavy meson production at large energies and forward rapidities at the LHC is fundamental to derive realistic predictions of the prompt atmospheric neutrino flux at the IceCube Observatory. In particular, the prompt tau neutrino flux is determined by the decay of Ds mesons produced in cosmic ray–air interactions at high energies and large values of the Feynman-xF variable. Recent data of the LHCb Collaboration indicate a production asymmetry for Ds+ and Ds− mesons, which cannot be explained in terms of the standard modeling of the hadronization process. In this paper we demonstrate that this asymmetry can be described assuming an asymmetric strange sea (s(x)≠s¯(x)) in the proton wave function and taking into account the dominant charm and subdominant strange fragmentation into Ds mesons. Moreover, we show that the strange quark fragmentation contribution is dominant at large-xF (≥0.3). The prompt ντ flux is calculated and the enhancement associated with the strange quark fragmentation contribution, disregarded in previous calculations, is estimated. The considered scenario leads to quite sizable enhancement of the high-energy τ-neutrino flux.

Народження S-бозона в реакції кулонівського розсіяння ядра на протоні або електроні

The production cross-section of the beyond the standard model (BSM) scalar boson (S boson) have been considered it the article. Scalar boson produced via photon fusion reaction in the deep inelastic scattering of a charged particle (proton or electron) on heavy nucleus of the target. This process is one of the possible mechanisms of BSM boson production at the SHiP (Search for Hidden Particles) experiment at the CERN LHC and may be dominating among others processes due to large nuclear charge. Previously [1], the amplitude and the production cross-section of this reaction were found. The found cross-section was analyzed for the case of proton scattering on the lead nucleus and compared with the production cross-section in the decay of Ds meson. In this paper we make estimate of the process more accurate and consider also electron-nucleus scattering. It was found that the photon fusion reaction pZ \to S may be effective only in the case of massless S boson.

Обрахунок перерізу народження BSM бозона в реакції фотонного злиття

The production cross-section of the beyond the standard model (BSM) scalar boson (S-boson) have been considered it the article. Scalar boson produced via photon fusion reaction in the deep inelastic scattering of a charged particle (proton or electron) on heavy nucleus of the target. This process is one of the possible mecha- nisms of BSM boson production at the SHiP (Search for Hidden Particles) experiment at the CERN LHC and may be dominating among others processes due to large nuclear charge. In a low-energy case for which virtual photon wavelength similar or bigger nuclear size one can consider nucleus as an elementary particle with the charge Z. Corresponding amplitude is proportional to Z and the cross-section proportional to Z^2. Due to this the alpha_{EM}^2 suppression of the production cross-section is approximately compensated by the charge number factor Z^2. The mass of boson cannot exceed 4 MeV for the incident proton (or less than 80 MeV for electron). We calculated amplitude and the production cross-section of this reaction directly without using equivalent photon approximation. Interaction between photon and neutral boson is described by triangular diagrams with the loop containing all charged leptons, quarks and W-bosons. For this interaction we used effective lagrangian. The found cross-section was analyzed for the case of proton scattering on the lead nucleous and compared with the production cross-section in the decay of Ds mesons. It was found that the photon fusion reaction becomes effective only with a S-boson mass less than 0.1 keV.

Study of tau neutrino production at the CERN SPS

At the CERN SPS, the DsTau project has been proposed to study tau-neutrino production aiming at providing important information for future ντ measurements. Precise measurement of the ντ cross section would enable a search for new physics effects in ντ charged current interactions. It also has practical implications for neutrino oscillation experiments. The dominant source of ντ is the sequential decay of Ds mesons produced by proton interactions, whose uncertainty dominates current uncertainty in the ντ cross section measurement. The project aims at reducing the systematic uncertainty from about 50% to 10% by measuring the Ds differential production cross section. For this purpose, emulsion detectors with a nanometre-precision readout will be used to detect small kinks of the Ds → τ decay. An emulsion detector has a position resolution of 50 nm, allowing for the detection of Ds → τ → X double kinks in a few millimeter range.

Open-charm physics: from e+e− to p̄p machines

This report intends to summarize the most interesting experimental results in open-charm physics achieved by the past e+e− experiments, and show some new theoretical developments, in particular for Ds mesons, for the cross section calculations in p̄p annihilation processes. After the observation of the , more than 10 years ago, still questions remain opened due to the lack of precision measurements. The measurement of the width of narrow states below the threshold in this respect is essential for a better understanding: a technique to measure that will be shown, and an overview on new future facilities where this measurement can be achieved will be given. In particular, we will focus on the role of the future P̄ANDA experiment at FAIR, and the unique contribution of this project in the measurement of the very narrow widths.

The decay constants fD and {f}_{D_s} in the continuum limit of Nf = 2 + 1 domain wall lattice QCD

We present results for the decay constants of the D and Ds mesons computed in lattice QCD with Nf = 2 + 1 dynamical flavours. The simulations are based on RBC/UKQCD’s domain wall ensembles with both physical and unphysical light-quark masses and lattice spacings in the range 0.11-0.07 fm. We employ the domain wall discretisation for all valence quarks.The results in the continuum limit are fD = 208.7(2.8)stat(− 1.8+ 2.1)sysMeV and {f}_{D_s}=246.4{(1.3)}_{mathrm{stat}}{left({}_{-1.9}^{+1.3}right)}_{mathrm{sys}}mathrm{M}mathrm{e}mathrm{V} and {f}_{D_s}={f}_D=1.667{(77)}_{mathrm{stat}}{left({}_{-43}^{+57}right)}_{mathrm{sys}} . Using these results in a Standard Model analysis we compute the predictions |Vcd| = 0.2185(50)exp(− 37+ 35)lat and |Vcs| = 1.011(16)exp(− 9+ 4)lat for the CKM matrix elements.

Formula omitted] meson production in Au+Au collisions measured by the STAR experiment

In these proceedings, we present the first measurements of the nuclear modification factor (RAA) and elliptic flow (v2) for the Ds meson within the rapidity range |y|<1 in Au+Au collisions at sNN=200 GeV from the STAR experiment. These results are compared with those of the D0 meson to study the hadronization mechanism of the charm quarks and probe the transport properties of the quark-gluon plasma [He M., Fries R. J., and Rapp R., Phys. Rev. Lett. 110, 112301 (2013)]. The DsRAA is found to be systematically higher than unity and D0RAA. The ratio of Ds/D0 yields in 10–40% central Au+Au collisions is also higher than that in p+p collisions as estimated by PYTHIA. All those indicate an enhancement of the Ds meson production in Au+Au collisions. The Ds/D0 yield ratio is also compared to that in Pb+Pb collisions at sNN=2.76 TeV measured by the ALICE experiment, and they seem to follow the same trend.

Measurements of open charm hadrons at the STAR experiment

Because of their large masses, charm quarks are predominantly produced in the early stages of the heavy-ion collisions via hard scatterings. Therefore, they experience the entire evolution of the Quark-Gluon Plasma created in such collisions. Compared to light quarks, charm quarks thermalize more slowly. Therefore, the open charm hadrons present a unique probe to the properties of the hot and dense nuclear matter by measuring their energy loss and degree of thermalization in the medium. Furthermore, with the combined measurements of D0 and Ds mesons, we can study multiple modes of coalescence of charm quarks with light quarks in heavy-ion collisions. Heavy Flavor Tracker at the STAR experiment enables full topological reconstruction of open charm hadrons which greatly improves measurements of D0 mesons and opens the door to reconstructing the Ds mesons for the first time at RHIC. In this paper, we present the nuclear modification factor and azimuthal anisotropy for the D0 and Ds mesons as well as the ratio of Ds/D0 in Au+Au collisions at the center-of-mass energy .

Lattice study of D and Ds meson form factors with twisted boundary conditions

We present results on the D and $D_{s}$ meson electromagnetic form factors using $N_{f}=2$ twisted mass Lattice Quantum Chromodynamics (LQCD) gauge configurations. In this simulation, to access spatial components of momenta that are different from the integer multiples of $2\pi /L$ , we apply twisted boundary conditions to compute corresponding correlation functions. Electromagnetic form factors with more small four-momentum transfer are determined, and further we fit the electromagnetic charge radius for D and $D_{s}$ mesons, respectively.