Meson-meson processes in strong interactions
Based on the meson-exchange framework the present work investigates the role played by meson-meson processes in strong interaction dynamics. We concentrate on two particular topics, one representing the more fundamental aspects of meson-meson systems the other being an example for the many possible applications. Using realistic meson-exchange models for ππ- and πη-scattering the first part of this work investigates the structure of the scalar meson f0(980) and a0(980) both being of outstanding importance for our understanding of the scalar meson sector. Our model produces good agreement with the available data. Furthermore, an analysis of the pole structure of the underlying ππ- and πη-scattering amplitudes leads to an understanding of the nature and parameters of f0(980) and a0(980). It is shown that besides the observed relationship between f0(980) and a0(980) their underlying structure is quite different. The second part of our investigation deals with the role played by correlated πρ exchange in the NN interaction. Starting point are open questions concerning the structure of the πNN vertex function. In the Bonn potential of the NN interaction a rather ''hard'' πNN formfactor is required in order to be able to reproduce experimental data, in particular the deuteron properties. However, this result is in disagreement with predictions from several theoretical models requiring a much softer πNN formfactor. We are able to show that this discrepancy is removed if correlated πρ exchange is added to the Bonn potential. (orig.)
The authors discuss why QCD leads to the search for exotic hadrons. They summarize some expectations from theory and models concerning the masses, decay pattern and characteristic features of glueballs (gg), hybrid (q bar qg) and diquonia (qq bar q bar q) mesons. They discuss the best known or more interesting candidates for exotic mesons
Vector-meson dominance revisited
Terschlüsen Carla
2012-12-01
Full Text Available The interaction of mesons with electromagnetism is often well described by the concept of vector-meson dominance (VMD. However, there are also examples where VMD fails. A simple chiral Lagrangian for pions, rho and omega mesons is presented which can account for the respective agreement and disagreement between VMD and phenomenology in the sector of light mesons.
Mesonic effects in nuclear physics
The relation between mesons and nucleons and the properties of nuclear matter, as presently understood, is considered in these lectures. Feynman diagrams, meson theoretical nucleon-nucleon interactions, mesonic components in nuclear wave functions, direct observation of mesonic components in NN scattering above the pion production threshold, nuclear matter theory, and pion condensation are treated. 120 references
Ajay Kumar Rai; P C Vinodkumar
2006-05-01
The mass spectrum of $c\\bar{b}$ meson is investigated with an effective quark-antiquark potential of the form $\\dfrac{-_{c}}{r} + Ar^{}$ with varying from 0.5 to 2.0. The and -wave masses, pseudoscalar decay constant, weak decay partial widths in spectator model and the lifetime of c meson are computed. The properties calculated here are found to be in good agreement with other theoretical and experimental values at potential index, = 1.
Transversity and Meson Photoproduction
Goldstein, G R; Goldstein, Gary R.; Gamberg, Leonard
2002-01-01
Both meson photoproduction and semi-inclusive deep inelastic scattering can potentially probe transversity in the nucleon. We explore how that potential can be realized dynamically. The role of rescattering in both exclusive and inclusive meson production as a source for transverse polarization asymmetry is examined. We use a dynamical model to calculate the asymmetry and relate that to the transversity distribution of the nucleon.
ρ meson decays of heavy hybrid mesons
Zhang, Liang; Huang, Peng-Zhi
2016-07-01
We calculate the ρ meson couplings between the heavy hybrid doublets Hh/Sh/Mh/Th and the ordinary qQ̅ doublets in the framework of the light-cone QCD sum rule. The sum rules obtained rely mildly on the Borel parameters in their working regions. The resulting coupling constants are rather small in most cases. Supported by National Natural Science Foundation of China (11105007)
Observation of exotic meson production in the reaction π- p → η(prime) π- p at 18 GeV/c
An amplitude analysis of an exclusive sample of 5765 events from the reaction π- p → η(prime)π- p at 18 GeV/c is described. The η(prime)π- production is dominated by natural parity exchange and by three partial waves: those with JPC = 1-+, 2++, and 4++. A mass-dependent analysis of the partial-wave amplitudes indicates the production of the a2(1320) meson as well as the a4(2040) meson, observed for the first time decaying to η(prime)π-. The dominant, exotic (non-q(bar q)) 1-+ partial wave is shown to be resonant with a mass of 1.597 ± 0.010-0.010+0.045 GeV/c2 and a width of 0.340 ± 0.040 ± 0.050 GeV/c2. This exotic state, the π1(1600), is produced with a t dependence which is different from that of the a2(1320) meson, indicating differences between the production mechanisms for the two states
The plasma phase at high temperatures of a strongly coupled gauge theory can be holographically modelled by an AdS black hole. Matter in the fundamental representation and in the quenched approximation is introduced through embedding D7-branes in the AdS-Schwarzschild background. Low spin mesons correspond to the fluctuations of the D7-brane world volume. As is well known by now, there are two different kinds of embeddings, either reaching down to the black hole horizon or staying outside of it. In the latter case the fluctuations of the D7-brane world volume represent stable low spin mesons. In the plasma phase we do not expect mesons to be stable but to melt at sufficiently high temperature. We model the late stages of this meson melting by the quasinormal modes of D7-brane fluctuations for the embeddings that do reach down to the horizon. The inverse of the imaginary part of the quasinormal frequency gives the typical relaxation time back to equilibrium of the meson perturbation in the hot plasma. We briefly comment on the possible application of our model to quarkonium suppression
Static-light meson-meson potentials
Bali, Gunnar
2010-01-01
We investigate potentials between pairs of static-light mesons in Nf=2 Lattice QCD, in different spin channels. The question of attraction and repulsion is particularly interesting with respect to the X(3872) charmonium state and charged candidates such as the Z+(4430). We employ the nonperturbatively improved Sheikholeslami-Wohlert fermion and the Wilson gauge actions at a lattice spacing a approx. 0.084 fm and a pseudoscalar mass mPS approx. 760 MeV. We use stochastic all-to-all propagator techniques, improved by a hopping parameter expansion. The analysis is based on the variational method, utilizing various source and sink interpolators.
The search for I = 0 0++ mesons is described. The crucial role played by the states in the 1 GeV region is highlighted. An analysis program that with unimpeachable data would produce definitive results on these is outlined and shown with present data to provide prima facie evidence for dynamics beyond that of the quark model. The authors briefly speculate on the current status of the lowest mass scalar mesons and discuss how experiment can resolve the unanswered issues. 30 references, 6 figures, 1 table
Techniques in meson spectroscopy
This report contains lectures on the following topics: the quark model and beyond using quantum chromodynamics; analysis of formation reactions; energy dependence of the partial wave amplitudes; where the data for the t-matrix analysis comes from; and coupled channel analysis of isoscalar mesons
Vento, Vicente [Consejo Superior de Investigaciones Cientificas, Departamento de Fisica Teorica y Instituto de Fisica Corpuscular, Universidad de Valencia, Burjassot (Spain)
2016-01-15
Calculations in unquenched QCD for the scalar glueball spectrum have confirmed previous results of Gluodynamics finding a glueball at ∝1750 MeV. I analyze the implications of this discovery from the point of view of glueball-meson mixing in light of the experimental scalar spectrum. (orig.)
Exclusive and inclusive decays of B mesons into Ds mesons
We have studied the production of Ds mesons in the decays of B mesons at the Υ(4S) resonance. We report on the first observation of exclusive B-meson decays B→Ds-D*+, B→Ds-D+, and B→Ds-D0. We also present a new measurement of the branching ratio and the momentum spectrum for the inclusive decay B→DsX
Light Meson Distribution Amplitudes
Arthur, R; Brommel, D; Donnellan, M A; Flynn, J M; Juttner, A; de Lima, H Pedroso; Rae, T D; Sachrajda, C T; Samways, B
2010-01-01
We calculated the first two moments of the light-cone distribution amplitudes for the pseudoscalar mesons ($\\pi$ and $K$) and the longitudinally polarised vector mesons ($\\rho$, $K^*$ and $\\phi$) as part of the UKQCD and RBC collaborations' $N_f=2+1$ domain-wall fermion phenomenology programme. These quantities were obtained with a good precision and, in particular, the expected effects of $SU(3)$-flavour symmetry breaking were observed. Operators were renormalised non-perturbatively and extrapolations to the physical point were made, guided by leading order chiral perturbation theory. The main results presented are for two volumes, $16^3\\times 32$ and $24^3\\times 64$, with a common lattice spacing. Preliminary results for a lattice with a finer lattice spacing, $32^3\\times64$, are discussed and a first look is taken at the use of twisted boundary conditions to extract distribution amplitudes.
According to the Standard Model of six quarks and six leptons, the charged-current decays of quarks can couple any of the up quarks, u, c, or t, to any of the down quarks, d, s, or b. Several of these couplings can be measured only in B-meson decays. It is important to measure them accurately in order to expand our knowledge of the model, to test its validity, and more importantly, to take us to a formulation of what is beyond. In the paper, the authors review the measurements that have been made on the weak decays of B mesons and discuss their implications for the matrix of quark couplings
Meson Spectroscopy without Tetraquarks
Bugg, D V
2011-01-01
Data on e+e- -> piplus-piminus-Upsilon(1S,2S,3S) show a large increase in branching fractions near Upsilon(10860). A suggestion of Ali et al. is to interpret this as evidence for a tetraquark, Yb(10890) = b-bbar. However, it may also be interpreted in terms of Upsilon(10860) -> B-B*, B*B* and BsB*s above the open-b threshold, followed by de-excitation processes such as $BB* -> Upsilon (1S,2S,3S). In the charm sector, a hypothesis open to experimental test is that X,Y and Z peaks in the mass range 3872 to 3945 MeV may all be due to regular 3P1 and 3P2 c-cbar states (and perhaps 3P0) mixed with meson-meson.
Törnqvist, N. A.; Spanier, S.(University of Tennessee, Knoxville, USA); Amsler, C
2008-01-01
This biennial Review summarizes much of particle physics. Using data from previous editions, plus 2778 new measurements from 645 papers, we list, evaluate, and average measured properties of gauge bosons, leptons, quarks, mesons, and baryons. We also summarize searches for hypothetical particles such as Higgs bosons, heavy neutrinos, and supersymmetric particles. All the particle properties and search limits are listed in Summary Tables. We also give numerous tables, figures, formulae, and re...
The nature of the scalar mesons in the 1 GeV region is studied. Analysis of all high statistics data in the neighbourhood of Kanti K threshold, in particular the fine-binned spectra on ψ → φ(ππ), φ(Kanti K) from DM2 and Mark III, indicate in an almost model-independent way that the f0(S*) is not a Kanti K molecule. (orig.)
A heavy particle with an unusual decay pattern discovered by the Belle experiment at KEK in Japan is the latest addition to the meson family tree. If we had to name a modern-day Mendeleev, his name would surely be Murray Gell-Mann. In the 1960s, faced with a bewildering array of particles called hadrons that had been turning up in high-energy experiments around the world, Gell-Mann proposed that the particles were combinations of a few fundamental entities called quarks. This idea brought order into the hadronic chaos, a feat for which Gell-Man was awarded the 1969 Nobel Prize for Physics. Ever since the quark model was introduced, physicists have wanted to find out how the six different types of quarks - up (u), down (d), strange (s), charm (c), bottom (b) and top (t) - combine to form the hadrons we observe. The simple hadronic structures that we see are easy to define: mesons such as pions and kaons consist of a quark and an antiquark pair, while baryons such as protons and neutrons are made up of three quarks or three antiquarks. But the theory that describes quarks, quantum chromodynamics (QCD), also permits particles containing four or more quarks. Indeed, a meson can be more generally defined as a hadron that has an integer value of intrinsic angular momentum in quantum units, while baryons have half-integer multiples of spin. Discovering such exotic hadrons, particularly mesons with more than the minimal quark-antiquark structure, would therefore provide crucial information for our understanding of the strong force. In fact, physicists thought they had glimpsed a five-quark state called a 'pentaquark' in 2003. Sadly this excitement looks as if it was misplaced, since the latest results from dedicated experimental searches suggest that pentaquarks are a purely statistical phenomenon (see Physics World May p7: print edition only). (U.K.)
Heavy meson production at HERA
Figiel Jan
2014-01-01
Full Text Available The copious production of charm mesons at HERA has allowed QCD to be probed in open charm and charm vector meson production. Elastic and proton-dissociatve photoproduction of J/ψ mesons have been measured at HERA. The data are compared to other measurements and the W and t dependences are parametrised using phenomenological fits. The ψ (2S state has also been measured exclusively and the ratio of its production rate to J/ψ mesons presented as a function of the kinematic variables. Inelastic production of J/ψ and ψ(2S mesons gives insight into non-relativistic QCD and final results are presented here. Open charm production has been measured in order to better understand the fragmentation process of charm mesons as well as giving insight into the structure of the proton.
Future prospects for exotic mesons
A brief description is given of the current status of exotic mesons produced in π-p interactions at 18 GeV/c-carried out with the BNL multiparticle spectrometer. The next logical step in our endeavor to understand the gluonic degrees of freedom in mesons is to extend the search for exotic mesons with hidden strangeness in K-p interactions at beam momenta in the range 15 to 25 GeV/c. (orig.)
Tolos, L; Garcia-Recio, C; Molina, R; Nieves, J; Oset, E; Ramos, A
2010-01-01
The properties of charmed mesons in dense matter are studied using a unitary coupled-channel approach in the nuclear medium which takes into account Pauli-blocking effects and meson self-energies in a self-consistent manner. We obtain the open-charm meson spectral functions in this dense nuclear environment, and discuss their implications on hidden charm and charm scalar resonances and on the formation of $D$-mesic nuclei at FAIR.
MIXING AND CP VIOLATION IN D MESONS
Yaouanc, A. Le; Oliver, L.; Pène, O; Raynal, J. -C.
1995-01-01
We review mixing and CP violation in $D$ mesons, emphasizing the differences with the other pseudoscalar mesons in the Standard Model, and show that $D$ mesons can be useful to look for physics beyond the Standard Model.
Charmed mesons in nuclear matter
Tolos, L; Garcia-Recio, C; Oset, E; Molina, R; Nieves, J; Ramos, A
2010-01-01
We obtain the properties of charmed mesons in dense matter using a coupled-channel approach which accounts for Pauli blocking effects and meson self-energies in a self-consistent manner. We study the behaviour of dynamically-generated baryonic resonances together with the open-charm meson spectral functions in this dense nuclear environment. We discuss the implications of the in-medium properties of open-charm mesons on the $D_{s0}(2317)$ and the predicted X(3700) scalar resonances, and on the formation of $D$-mesic nuclei.
Rare B Meson Decays With Omega Mesons
Zhang, Lei; /Colorado U.
2006-04-24
Rare charmless hadronic B decays are particularly interesting because of their importance in understanding the CP violation, which is essential to explain the matter-antimatter asymmetry in our universe, and of their roles in testing the ''effective'' theory of B physics. The study has been done with the BABAR experiment, which is mainly designed for the study of CP violation in the decays of neutral B mesons, and secondarily for rare processes that become accessible with the high luminosity of the PEP-II B Factory. In a sample of 89 million produced B{bar B} pairs on the BABAR experiment, we observed the decays B{sup 0} {yields} {omega}K{sup 0} and B{sup +} {yields} {omega}{rho}{sup +} for the first time, made more precise measurements for B{sup +} {yields} {omega}h{sup +} and reported tighter upper limits for B {yields} {omega}K* and B{sup 0} {yields} {omega}{rho}{sup 0}.
Exotic mesons: status and future
Klempt, Eberhard
2007-01-01
The evidence for the existence of mesons with exotic quantum numbers and of hybrid candidates with non-exotic quantum numbers is critically reviewed, including candidates with hidden charm. Aims and methods of future searches for hybrid mesons are briefly discussed.
Mesonic theory of effective forces
The construction of nucleon-nucleon effective interaction on base of meson theory of nuclear forces is considered. The dependence of effective force parameters from coupling constants and masses of the exchange mesons is investigated. The results of nuclear matter calculations are presented. 36 refs.; 9 figs.; 2 tabs
Exotic meson spectroscopy with CLAS
Adams, G.; Napolitano, J. [Rensselaer Polytechnic Inst., Troy, NY (United States)
1994-04-01
The identification and study of mesons with explicit gluonic degrees of freedom will provide major constraints on nonperturbative QCD and models thereof. CLAS will provide a unique opportunity for studying these resonances by measuring photoproduction of multi-meson final states.
The author calculates the form factors describing semileptonic and penguin induced decays of B mesons into light pseudoscalar and vector mesons. The form factors are calculated from QCD sum rules on the light-cone including contributions up to twist 4, radiative corrections to the leading twist contribution and SU(3) breaking effects. The theoretical uncertainty is estimated to be tilde (15--20)%
The light meson spectroscopy program
Smith Elton S.
2014-06-01
Full Text Available Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.
Meson Resonances from Lattice QCD
Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-06-01
There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems.
Meson resonances on the lattice
Edwards, Robert G. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-06-01
There has been recent, significant, advances in the determination of the meson spectrum of QCD. Current efforts have focused on the development and application of finite-volume formalisms that allow for the determination of scattering amplitudes as well as resonance behavior in coupled channel systems. I will review some of these recent developments, and demonstrate the viability of the method in meson systems
K^* Mesons and Nucleon Strangeness
Barz, L. L.; Forkel, H.; Hammer, H. -W.; Navarra, F. S.; Nielsen, M; Ramsey-Musolf, M. J.
1998-01-01
We study contributions to the nucleon strange quark vector current form factors from intermediate states containing K^* mesons. We show how these contributions may be comparable in magnitude to those made by K mesons, using methods complementary to those employed in quark model studies. We also analyze the degree of theoretical uncertainty associated with K^* contributions.
The light meson spectroscopy program
Smith, Elton S. [JLAB
2014-06-01
Recent discoveries of a number of unexpected new charmomium-like meson states at the BaBar and Belle B-factories have demonstrated how little is still known about meson spectroscopy. In this talk we will review recent highlights of the light quark spectroscopy from collider and fixed target experiments.
Heavy meson fragmentation at LHC
M. A. Gomshi Nobary
2003-06-01
Full Text Available Large Hadron Collider (LHC at CERN will provide excellent opportunity to study the production and decay of heavy mesons and baryons with high statistics. We aim at the heavy mesons in this work and calculate their fragmentation functions consistent with this machine and present their total fragmentation probabilities and average fragmentation parameters.
Using the ARGUS detector at the e+e- storage ring DORIS II at DESY, we have measured the lifetimes of the D0, D+ and Ds+ mesons. We find τsub(D0) = (4.8±0.4±0.3)x10-13 s, τsub(D+) = (10.5±0.8±0.7)x10-13 s and τsub(Ds+) = (5.6-1.2+1.3±0.8)x10.13s. (orig.)
Photoproduction of Hybrid Mesons
Barnes, T.
1999-01-01
In this contribution I discuss prospects for photoproducing hybrid mesons at CEBAF, based on recent model results and experimental indications of possible hybrids. One excellent opportunity appears to be a search for the I=1, JPC=2+-, neutral "(b2)o" hybrid in (a2 pi)o through diffractive photoproduction. Other notable possibilities accessible through pi+ or pio exchange photoproduction are I=1, JPC=1-+, charged "pi1+" in f1 pi+, (b1 pi)+ and (rho pi)+; piJ(1770)+ in f2 pi+ and (b1 pi)+; pi(1...
Physics opportunities with meson beams
Briscoe, William J.; Doering, Michael; Haberzettl, Helmut; Strakovsky, Igor I. [The George Washington University, Washington, DC (United States); Manley, D.M. [Kent State University, Kent, OH (United States); Naruki, Megumi [Kyoto University, Kyoto (Japan); Swanson, Eric S. [University of Pittsburgh, Pittsburgh, PA (United States)
2015-10-15
Over the past two decades, meson photo- and electroproduction data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even non-existent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledge in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state-of-the-art meson-beam facility needs to be constructed. The present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility. (orig.)
Physics Opportunities with Meson Beams
Briscoe, William J; Haberzettl, Helmut; Manley, D Mark; Naruki, Megumi; Strakovsky, Igor I; Swanson, Eric S
2015-01-01
Over the past two decades, meson photo- and electro-production data of unprecedented quality and quantity have been measured at electromagnetic facilities worldwide. By contrast, the meson-beam data for the same hadronic final states are mostly outdated and largely of poor quality, or even nonexistent, and thus provide inadequate input to help interpret, analyze, and exploit the full potential of the new electromagnetic data. To reap the full benefit of the high-precision electromagnetic data, new high-statistics data from measurements with meson beams, with good angle and energy coverage for a wide range of reactions, are critically needed to advance our knowledge in baryon and meson spectroscopy and other related areas of hadron physics. To address this situation, a state of-the-art meson-beam facility needs to be constructed. The present paper summarizes unresolved issues in hadron physics and outlines the vast opportunities and advances that only become possible with such a facility.
Grube, Boris
2015-01-01
The COmmon Muon and Proton Apparatus for Structure and Spectroscopy (COMPASS) is a multi-purpose fixed-target experiment at the CERN Super Proton Synchrotron (SPS) aimed at studying the structure and spectrum of hadrons. The two-stage spectrometer has a good acceptance for charged as well as neutral particles over a wide kinematic range and thus allows to access a wide range of reactions. Light mesons are studied with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The spectrum of light mesons is investigated in various final states produced in diffractive dissociation reactions at squared four-momentum transfers to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^+\\pi^-$ final state, for which COMPASS has recorded the currently largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to search for new states. Among these is a new resonance-like signal, t...
Meson radiobiology and therapy
High-linear energy transfer radiation (neutrons, heavy ions, and pions) have a greater relative biological effectiveness than low-linear energy transfer radiation by depositing a high density of ionization in irradiated cells. This overcomes the protective effect of oxygen; decreases the variation in sensitivity among the several stages of the cell cycles; and, inhibits the repair of sublethal damage as compared to x-rays, gamma rays, electrons and protons. Negative pi mesons (pions), appear particularly suited for radiation therapy as their penetration and depth-dose profiles lend themselves to shaping the high dose area to the tumor size and location. Preliminary biological experiments with pions produced at the Los Alamos Meson Physics Facility studied cell survival at various radiation depths and cell cycle sensitivity. Histologic study of data from the first human experiments indicated severe tumor cell destruction by pions as compared to x-rays in treating malignant melanoma skin nodules, without increased effects on dermal elements. (U.S.)
,
2016-01-01
The goal of the COMPASS experiment at CERN is to study the structure and dynamics of hadrons. The two-stage spectrometer used by the experiment has large acceptance and covers a wide kinematic range for charged as well as neutral particles and can therefore measure a wide range of reactions. The spectroscopy of light mesons is performed with negative (mostly $\\pi^-$) and positive ($p$, $\\pi^+$) hadron beams with a momentum of 190 GeV/$c$. The light-meson spectrum is measured in different final states produced in diffractive dissociation reactions with squared four-momentum transfer $t$ to the target between 0.1 and 1.0 $(\\text{GeV}/c)^2$. The flagship channel is the $\\pi^-\\pi^-\\pi^+$ final state, for which COMPASS has recorded the currently world's largest data sample. These data not only allow to measure the properties of known resonances with high precision, but also to observe new states. Among these is a new axial-vector signal, the $a_1(1420)$, with unusual properties. Novel analysis techniques have been...
Photon-meson transition form factors of light pseudoscalar mesons
Xiao, Bo-Wen; Ma, Bo-Qiang
2005-01-01
The photon-meson transition form factors of light pseudoscalar mesons $\\pi ^{0}$, $\\eta$, and $\\eta ^{\\prime}$ are systematically calculated in a light-cone framework, which is applicable as a light-cone quark model at low $Q^{2}$ and is also physically in accordance with the light-cone pQCD approach at large $Q^{2}$. The calculated results agree with the available experimental data at high energy scale. We also predict the low $Q^{2}$ behaviors of the photon-meson transition form factors of ...
Eta'-meson as pseudoscalar gluonium
It is proved the sum rules of quantum chromodynamics for a current constructed of the gluon field operators are saturated by the eta'-meson. The meson mass is estimated and its residue in the gluon current. There is a considerable difference between the eta'-meson as gluon and the classical quark states such as the delta-meson. (orig.)
Rotating strings confronting PDG mesons
Jacob Sonnenschein; Dorin Weissman
2014-01-01
We revisit the model of mesons as rotating strings with massive endpoints and confront it with meson spectra. We look at Regge trajectories both in the ( J, M 2 ) and ( n, M 2 ) planes, where J and n are the angular momentum and radial excitation number respectively. We start from states comprised of u and d quarks alone, move on to trajectories involving s and c quarks, and finally analyze the trajectories of the heaviest observed b b ¯ $$ b\\overline{b} $$ mesons. The endpoint masses provide...
In this article we give a review of certain aspects of the present understanding of spectroscopy of heavy mesons and constituent quark masses in the light of non-relativistic potential model approach motivated by quantum chromodynamics. We find that the one gluon exchange at short distance and colour-confining interaction at large distance which is pure scalar (or scalar-vector admixture with dominant scalar interaction) under the Lorentz transformation, can explain only partially the present data on 1P states of cc-bar and bb-bar states. The S-wave data, that are available at present, however can be understood with both scalar confinement or scalar-vector admixture with scalar-dominant interaction. (author). 44 refs, 13 tabs
Gy Wolf
2006-04-01
One consequence of the chiral restoration is the mixing of parity partners. We look for a possible signature of the mixing of vector and axial vector mesons in heavy-ion collisions. We suggest an experimental method for its observation. The dynamical evolution of the heavy-ion collision is described by a transport equation of QMD-type evolving nucleons, * and resonances, ’s and $\\sum$ baryons, and furthermore, ’s, ’s ’s ’s ’s and kaons with their isospin degrees of freedom. The input cross-sections and resonance parameters of the model are fitted to the available nucleon–nucleon and pion–nucleon cross-sections.
Meson spectroscopy with unitary coupled-channels model for heavy-meson decay into three mesons
Nakamura, Satoshi X.
2012-01-01
We develop a model for describing excited mesons decay into three mesons. The properties of the excited mesons can be extracted with this model. The model maintains the three-body unitarity that has been missed in previous data analyses based on the conventional isobar models. We study an importance of the three-body unitarity in extracting hadron properties from data. For this purpose, we use the unitary and isobar models to analyze the same pseudo data of gamma p -> pi+pi+pi-n, and extract ...
An introduction to heavy mesons
Grinstein, B
1995-01-01
Introductory lectures (delivered at the VI Mexican School of Particles and Fields) on heavy quarks and heavy quark effective field theory. Applications to inclusive semileptonic decays and to interactions with light mesons are covered in detail.
D meson decay channels that involve light scalar mesons
Fariborz, Amir
2013-04-01
A generalized linear sigma model of low-energy QCD is used to study several decay channels of D mesons that involve light scalar meson as a decay product. Such studies require reliable models for scalar mesons that take into account underlying mixing among quark-antiquarks, tetra quarks and glueballs. In this talk, the generalized linear sigma model of low-energy QCD for understanding the properties of scalar mosons will be briefly presented, and he application of this model to studies of heavier meson decays [such as the semileptonic decay Ds(1968)->f0(980) e^+ ν] will be presented, and a few directions for further extensions of the model will be outlined. Refs. A.H. Fariborz, R. Jora, J. Schechter and M.N. Shahid, ``Semi-leptonic Ds^+(1968) Decays as a Scalar Meson Probe,'' Physical Review D 84, 094024 (2011). A.H. Fariborz, R. Jora, J. Schechter and M.N. Shahid, ``Chiral Nonet Mixing in pi-pi Scattering,'' Physical Review D 84, 113004 (2011).
A Constituent Quark-Meson Model for Heavy Meson Decays
Deandrea, Aldo
1998-01-01
I describe a model for heavy meson decays based on an effective quark-meson lagrangian. I consider the heavy mesons S with spin and parity J^P=(1+,0+), H with J^P=(1-,0-) and T^mu with J^P=(2+,1+), i.e. S and P wave heavy-light mesons. The model is constrained by the known symmetries of QCD in the mQ -> infinity limit for the heavy quarks, and chiral symmetry in the light quark sector. Using a very limited number of free parameters it is possible to compute several phenomenological quantities, e.g. the leptonic B and B** decay constants; the three universal Isgur-Wise form factors: xi, tau(3/2), tau(1/2), describing the semi-leptonic decays B -> D(*) l nu, B -> D** l nu; the strong and radiative D* decays; the weak semi-leptonic decays of B and D into light mesons: pi, rho, a1. An overall agreement with data, when available, is achieved.
Cross sections for meson-meson nonresonant reactions
Li, Yu-Qi
2007-01-01
Meson-meson nonresonant reactions governed by the quark-interchange mechanism are studied in a potential that is derived from QCD. S-wave elastic phase shifts for I=2 \\pi\\pi and I=3/2 K \\pi scattering are obtained with wave functions determined by the central spin-independent term of the potential. The reactions include inelastic scatterings of two mesons in the ground-state pseudoscalar octet and the ground-state vector nonet. Cross sections for reactions involving pion, rho, K and K^* indicate that mesonic interactions in matter consisting of only K and K^* can be stronger than mesonic interactions in matter consisting of only pions and rhos and the reaction of I=3/2 \\pi K^* \\to \\rho K is most important among the endothermic nonresonant reactions. By the quark-interchange mechanism we can offer \\sqrt s-dependences of phi absorption cross sections in collisions with pion and rho and relevant average cross sections what are very small for the reaction of I=1 \\pi \\phi \\to K^* K^* and remarkably large for the r...
Photon-meson transition form factors of light pseudoscalar mesons
Xiao, B W; Xiao, Bo-Wen; Ma, Bo-Qiang
2005-01-01
The photon-meson transition form factors of light pseudoscalar mesons $\\pi ^{0}$, $\\eta $, and $\\eta ^{\\prime}$ are systematically calculated in a light-cone framework, which is applicable as a light-cone quark model at low $Q^{2}$ and is also physically in accordance with the light-cone pQCD approach at large $Q^{2}$. The calculated results agree with the available experimental data at high energy scale. We also predict the low $Q^{2}$ behaviors of the photon-meson transition form factors of $\\pi ^{0}$, $\\eta $ and $\\eta ^{\\prime }$, which are measurable in $e+A({Nucleus})\\to e+A+M$ process via Primakoff effect at JLab and DESY.
Meson Strings and Flavor Branes
Bando, M; Terunuma, S; Bando, Masako; Sugamoto, Akio; Terunuma, Sachiko
2006-01-01
In a QCD-like string model based on D6 flavor branes in the presence of D4 color branes wrapping one of the compactified dimension on an $S^1$, the shape of meson strings in the five dimensional curved space as well as the potential between quark and anti-quark are investigated. The flavor branes on which both ends of a meson string live are assumed to be separated in this five dimensional space, depending on the values of the constituent quark masses. It is shown in this picture that the meson string with different flavors on both ends changes its shape at a critical distance. There is, however, no critical distance for the meson with the same flavors. At this critical distance the potential between quark and anti-quark with different flavors gives a point of reflection and changes its shape around this point. Accordingly, the attractive force between quark and anti-quark seems to become stronger when the distance of flavor branes connecting meson strings becomes larger. This indicates quark systems with dif...
Beauty Meson Decays To Charmonium
Ershov, A V
2001-01-01
We study decays of beauty (B) mesons into the final states containing charmonium mesons. The data were collected by the CLEO experiment at the Cornell Electron Storage Ring from 1990 to 1999. First, we describe a technique that significantly improves the reconstruction efficiency for decays of J/ y and y (2S) mesons into a pair of leptons. This reconstruction method is used in all the analyses presented in this dissertation. Then we present a study of B decays to the χc 1 and χc2 charmonium states and compare our results with the predictions of different theoretical models of charmonium production. After that we report the first observation of the decay B → J/ y &phis;K, which is the first B meson decay requiring a creation of an additional ss¯ quark pair. Then we measure the B0 and B+ meson masses from B0 → y (′) K0S and B+ → y (′) K+ decays. The method employed eliminates the dominant systematic uncertainty associated w...
Search for rare B meson decays into Ds+ mesons
A search has been performed for rare B meson decays into Ds+ mesons arising from b→u transitions, W exchange modes, B+ annihilation processes, and decays where the Ds+ is not produced via a W→c anti s quark pair coupling, using the ARGUS detector operating on the Y(4S) resonance at the e+e- storage ring DORIS II. Upper limits for individual decay modes are obtained. In addition, from a study of Ds+l- correlations an upper limit of BR(B→Ds+l-X)<1.2%(90% CL) is determined. (orig.)
Vector meson-vector meson interaction and dynamically generated resonances
We report upon 11 composite meson states, dynamically generated from the vector meson–vector meson interaction using the local hidden gauge formalism within a unitary approach. Six of these states are associated to the f0(1370), f0(1710), f2(1270), f'2(1525), a2(1320) and K*2(1430) resonances. At the same time we predict five other states with the quantum numbers of h1, a0, b1, K*0, and K1 which could be tested by future experiments.
Neutral B meson flavor tagging
Wilson, R J
2001-01-01
We present an investigation of the use of net charge and kaon identification to tag the flavor of neutral B mesons. The net charge of the neutral B meson decay products is zero if all charged particles are used and slightly non-zero if only undiscriminated hadronic final states are used. The net charge of the kaons alone correctly tags the identity of the neutral meson in at least a third of all decays. We have parametrized the particle identification capability of several techniques, such as dE/dx in time projection chambers, LEP/SLC ring-imaging chambers and an enhanced BaBar DIRC. Using these parametrisations we compare the relative tagging power of each technique to that of an ideal detector. (8 refs).
The strange axial-vector mesons K1 (1270) and K1 (1400) are reanalyzed in the light of the updated experimental information and compared with the recent result on the Kππ production in τ decay. The mixing angle between the strange mesons of 3P1 and 1P1 is determined by the partial decay rates, and, independently, by the masses. They lead to θK∼33 degree or 57 degree. The observed K1 (1400) production dominance in the τ decay favors θK∼33 degree. Flavor-SU(3) breaking of 20% or so in the production amplitudes can explain quantitatively the observed production ratio
Beauty meson decays to charmonium
Ershov, Alexey Valerievich
2001-10-01
We study decays of beauty (B) mesons into the final states containing charmonium mesons. The data were collected by the CLEO experiment at the Cornell Electron Storage Ring from 1990 to 1999. First, we describe a technique that significantly improves the reconstruction efficiency for decays of J/ y and y (2S) mesons into a pair of leptons. This reconstruction method is used in all the analyses presented in this dissertation. Then we present a study of B decays to the χc 1 and χc2 charmonium states and compare our results with the predictions of different theoretical models of charmonium production. After that we report the first observation of the decay B --> J/ y φK, which is the first B meson decay requiring a creation of an additional ss¯ quark pair. Then we measure the B0 and B+ meson masses from B0 --> y (') K0S and B+ --> y (') K+ decays. The method employed eliminates the dominant systematic uncertainty associated with the previous B meson mass measurements at the e+e- colliders and results in a significant improvement in precision. After that we present a study of three B0 decay modes useful for time-dependent CP asymmetry measurements. In this study we reconstruct B0 --> J/ y K0S , B0 --> χc 1 K0S , and B0 --> J/ y π0 decays. The latter two decay modes are observed for the first time. We describe a K0S --> π0π0 detection technique and its application to the reconstruction of the decay B 0 --> J/ y K0S . Then we present a sensitivity study for the measurement of the mixing-induced CP violation in the neutral B meson system (parameter sin 2β) at CLEO using the method that requires a measurement of the decay time of only one meson in a B0overline B0 pair. Finally, we search for direct CP violation in decays B+/- --> J/ y K+/- and B +/- --> y (2S) K+/- . The results of this search are consistent with the Standard Model expectations and provide the first experimental test of the assumption that direct CP violation is negligible in B --> y (') K decays.
Status of light scalar mesons as non-ordinary mesons
In this talk I briefly review the status of the f0(500) and f0(980) together with the other light scalar resonances, as well as the emerging picture of a non-ordinary light meson multiplet, paying particular attention to unitarized Chiral Perturbation Theory, large Nc, semilocal duality and Regge theory arguments
Unraveling the pattern of the $XYZ$ mesons
Vijande, J
2015-01-01
We present a plausible mechanism for the origin of the $XYZ$ mesons in the heavy meson spectra within a standard quark-model picture. We discuss the conditions required for the existence of four--quark bound states or resonances contributing to the heavy meson spectra, being either compact or molecular. We concentrate on charmonium and bottomonium spectra, where several new states, difficult to understand as simple quark-antiquark pairs, have been reported by different experimental collaborations. The pivotal role played by entangled meson-meson thresholds is emphasized.
Theoretical overview: The New mesons
Quigg, Chris; /Fermilab
2004-11-01
After commenting on the state of contemporary hadronic physics and spectroscopy, I highlight four areas where the action is: searching for the relevant degrees of freedom, mesons with beauty and charm, chiral symmetry and the D{sub sJ} levels, and X(3872) and the lost tribes of charmonium.
Holographic mesons in various dimensions
Myers, R C; Myers, Robert C.; Thomson, Rowan M.
2006-01-01
We calculate the spectrum of fluctuations of a probe Dk-brane in the background of N Dp-branes, for k=p,p+2,p+4 and p< 5. The result corresponds to the mesonic spectrum of a (p+1)-dimensional super-Yang-Mills (SYM) theory coupled to `dynamical quarks', i.e., fields in the fundamental representation -- the latter are confined to a defect for k=p and p+2. We find a universal behaviour where the spectrum is discrete and the mesons are deeply bound. The mass gap and spectrum are set by the scale M ~ m_q/g_{eff}(m_q), where m_q is the mass of the fundamental fields and g_{eff}(m_q) is the effective coupling evaluated at the quark mass, i.e. g_{eff}^2(m_q)=\\gym^2N m_q^{p-3}. We consider the evolution of the meson spectra into the far infrared of three-dimensional SYM, where the gravity dual lifts to M-theory. We also argue that the mass scale appearing in the meson spectra is dictated by holography.
Local optical potentials for mesons
Full text: Local optical models are very useful to describe many nuclear reactions, with the parameters often determined from fits to data. Elastic meson-nucleus scattering can be described by such potentials, but there is a strong ambiguity in the parameters [1], making the model hard to apply. Consideration of meson-nucleus inelastic scattering to collective states can be described in the local DWBA, built on local optical models. If the parameters of the optical potential are varied so as to find simultaneous agreement with both elastic and inelastic scattering, the ambiguity is removed, and a unique local optical potential can be defined for mesons [2,3]. The methods used to determine these parameters, examples of the fits and the meaning of the results will be explained. The result is a widely usable set of parameters in a simple local optical potential for pion and kaon interactions with nuclei, found to describe these reactions over a wide range of beam energies and nuclear masses. This accomplishment should allow a wider range of nuclear reaction models to include mesons in a simple way
Kotulla, Martin
2006-01-01
We discuss recent experimental results on the modification of hadron properties in a nuclear medium. Particular emphasis is placed on an $\\omega$ production experiment performed by the CBELSA/TAPS collaboration at the ELSA accelerator. The data shows a smaller $\\omega$ meson mass together with a significant increase of its width in the nuclear medium.
Pseudoscalar meson form factors and decays
Dorokhov, A E
2011-01-01
In this communication we discuss few topics related with modern experimental data on the physics of light pseudoscalar mesons. It includes the contribution of the pseudoscalar mesons to the muon anomalous magnetic moment (AMM), $g-2$, the rare decays of light pseudoscalar mesons to lepton pair, the transition form factors of pseudoscalar mesons at large momentum transfer, the pion transversity form factor. Measuring the muon anomalous magnetic moment $g-2$ and the rare decays of light pseudoscalar mesons into lepton pair $P\\rightarrow l^{+}l^{-} $ serve as important test of the standard model. To reduce the theoretical uncertainty in the standard model predictions the data on the transition form factors of light pseudoscalar mesons play significant role. Recently new data on behavior of these form factors at large momentum transfer was supplied by the BABAR collaboration. Within the nonlocal chiral quark model it shown how to describe these data and how the meson distribution amplitude evolves as a function o...
Vector meson electroproduction in QCD
Based on the generalized QCD vector meson dominance model, we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model. Numerical calculations for the total cross section σtot and differential cross section dσ/dt are performed for ρ, ω and φ meson electroproduction in this paper. Since gluons interact among themselves (self-interaction), two gluons can form a glueball with quantum numbers IG, JPC = 0+, 2++, decay width Γt ≈ 100 MeV, and mass of mG=2.23 GeV. The three gluons can form a three-gluon colorless bound state with charge conjugation quantum number C = -1, called the Odderon. The mediators of interactions between projectiles (the quark and antiquark pair fluctuated from the virtual photon) and the proton target (a three-quark system) are the tensor glueball and the Odderon. Our calculated results in the tensor glueball and Odderon exchange model fit to the existing data successfully, which evidently shows that our present QCD mechanism is a good description of meson electroproduction off a proton. It should be emphasized that our mechanism is different from the theoretical framework of Block et al. We also believe that the present study and its success are important for the investigation of other vector meson electro- and photoproduction at high energies, as well as for searching for new particles such as tensor glueballs and Odderons, which have been predicted by QCD and the color glass condensate model (CGC). Therefore, in return, it can test the validity of QCD and the CGC model. (authors)
Vector meson electroproduction in QCD
LU Juan; CAI Xian-Hao; ZHOU Li-Juan
2012-01-01
Based on the generalized QCD vector meson dominance model,we study the electroproduction of a vector meson off a proton in the QCD inspired eikonalized model.Numerical calculations for the total cross section σtot and differential cross section dσ/dt are performed for p,ω and φ meson electroproduction in this paper.Since gluons interact among themselves (self-interaction),two gluons can form a glueball with quantum numbers IG,JPC =0+,2++,decay width Γt ≈ 100 MeV,and mass of mG=2.23 GeV.The three gluons can form a three-gluon colorless bound state with charge conjugation quantum number C =-1,called the Odderon.The mediators of interactions between projectiles (the quark and antiquark pair fluctuated from the virtual photon) and the proton target (a three-quark system) are the tensor glueball and the Odderon.Our calculated results in the tensor glueball and Odderon exchange model fit to the existing data successfully,which evidently shows that our present QCD mechanism is a good description of meson electroproduction off a proton.It should be emphasized that our mechanism is different from the theoretical framework of Block et al.We also believe that the present study and its success are important for the investigation of other vector meson electro- and photoproduction at high energies,as well as for searching for new particles such as tensor glueballs and Odderons,which have been predicted by QCD and the color glass condensate model (CGC).Therefore,in return,it can test the validity of QCD and the CGC model.
Terschlüsen, Carla
2016-01-01
The contributions of one-loop diagrams with dynamical vector mesons to masses and decay constants of pseudoscalar mesons are determined. Hereby, a relativistic Lagrangian for both the pseudoscalar-meson octet and the vector-meson nonet is used. The vector mesons are given in the antisymmetric tensor representation. Both the differences between static and dynamical vector mesons and the differences between calculations with and without vector mesons are studied as functions of the light quark mass.
On Deusons or Deuteronlike Meson-Meson Bound States
Törnqvist, N A
1994-01-01
The systematics of deuteronlike two-meson bound states, {\\it deusons}, is discussed. Previous arguments that many of the present non-$q\\bar q$ states are such states are elaborated including, in particular, the tensor potential. For pseudoscalar states the important observation is made that the centrifugal barrier from the P-wave can be overcome by the $1/r^2$ and $1/r^3$ terms of the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteron-like $B\\bar B^*$ and $B^*\\bar B^*$ composites bound by approximately 50 MeV, while $D\\bar D^*$ and $D^*\\bar D^*$ states are expected near the threshold.
Semileptonic decays of B meson into charmed meson
Recent results on semileptonic decays of B meson into charmed meson using the CLEO detector at CESR are summarized. Ratios of the inclusive semileptonic branching fractions, B(B-→D0Xl-bar ν), B(bar B0→D+Xl-bar νXl-bar ν), and B(bar B0→D+) average B meson semileptonic branching fraction are reported. The branching fractions of the exclusive final states, B-→D0l-bar ν, B-→D0l-bar ν, and bar B0→D+l-bar ν are measured. The ratio of B(B-→D0l-bar ν) to B(B-→D0l-bar ν) and the polarization of the D*+ are obtained and compared with theoretical models. The value of |Vcb| is calculated from the exclusive branching fractions for various models. Finally, the lifetime ratio of the charged and neutral B's (τ+/τ0) is determined from the ratio of B(B-→D0l-bar ν) to B(bar B0→D+l-bar ν) to be 0.85±0.20+0.22-0.16
Mesons on a transverse lattice
Dalley, S
2001-01-01
The meson eigenstates of the light-cone Hamiltonian in a coarse transverse lattice gauge theory are investigated. Building upon previous work in pure gauge theory, the Hamiltonian and its Fock space are expanded in powers of dynamical fields. In the leading approximation, the couplings appearing in the Hamiltonian are renormalised by demanding restoration of space-time symmetries broken by the cut-off. Additional requirements from chiral symmetry are discussed and difficulties in imposing them from first principles in the leading approximation are noted. A phenomenological calculation is then performed, in which chiral symmetry in spontaneously broken form is modelled by imposing the physical pion-rho mass splitting as a constraint. The light-cone wavefunctions of the resulting Hamiltonian are used to compute decay constants, form factors and quark momentum and spin distributions for the pion and rho mesons. Extensions beyond leading order, and the implications for first principles calculations, are briefly d...
Measurement of Charm Meson Lifetimes
We report measurements of the D0 , D+ , and D+s meson lifetimes using 3.7 fb-1 of e+e- annihilation data collected near the Υ(4S) resonance with the CLEO detector. The measured lifetimes of the D0 , D+ , and D+s mesons are 408.5±4.1+3.5-3.4 fs , 1033.6±22.1+9.9-12.7 fs , and 486.3±15.0+4.9-5.1 fs . The precision of these lifetimes are comparable to those of the best previous measurements, and the systematic errors are very different. In a single experiment we find that the ratio of the D+s and D0 lifetimes is 1.19±0.04 . copyright 1999 The American Physical Society
Resurrection of the $\\sigma$ meson
Törnqvist, N A; Tornqvist, Nils A; Roos, Matts
1995-01-01
It is shown from a very general model and an analysis of data on the lightest 0++ meson nonet that the f0(980) and f0(1200) resonance poles are two manifestations of the same ss state. Similarily the a0(980) and the a0(1450) are likely to be two manifestations of the same qq state. On the other hand, the uu+dd state, when unitarized and strongly distorted by hadronic mass shifts, becomes an extremely broad Breit-Wigner-like background, m=860 MeV, Gamma=880 MeV, with its pole at s=(0.158-i0.235) GeV^2. This we identify with the sigma meson required by models for spontaneous breaking of chiral symmetry.
Primakoff production of hybrid mesons
The viability of Primakoff technique in searching for hybrid states, and exotic JPC = 1-+ isovector meson bar ρ in particular, is discussed. Results of searches for Primakoff production of an bar ρ in ρπ and ηπ final states produced in high energy interactions of pions with large-Z nuclei are reviewed, and the limits for the radiative coupling Γ( bar ρ+ → π+γ) are presented. Based on available experimental information, electromagnetic production rate estimates are given for the favored bar ρ → πf1(1285) channel. It is argued that a dedicated Primakoff production experiment can be sensitive to values of Γ( bar ρ+ → π+γ) ∼ keV, which makes such measurement a very interesting option for doing spectroscopy of gluonic (and conventional) meson states in the 1.5 ∼ 3 GeV mass range. 18 references, 2 figures
Baryons and Mesons with Beauty
Goldstein, Gary R.; Wali, Kameshwar C.
2007-01-01
Recent experimental findings of several mesons and baryons with "beauty" and "charm" as flavors remind us of the days when strangeness was discovered, and how its inclusion led to SU(3)-flavor symmetry with enormous success in the classification of the "proliferated" states into SU(3) multiplets. One of the key elements was the successful application of the first order perturbation in symmetry breaking, albeit what then appeared to be huge mass differences, and the prediction of new states th...
A review is given of the nonleptonic decays of D mesons. Included are measurements of the psi(3772), the accurate determination of D masses and their consequences, and inclusive measurements and tagged events. It is noted that the distinction between the above designated events is that in the former one detects a D decay and ignores the remainder of the event, while in the tagged events a D decay is detected and also the remainder of the event is studied. 39 references
Exclusive meson production at HERMES
Manaenkov, Sergey
2016-01-01
The data were accumulated with the HERMES forward spectrometer using the 27.6 GeV longitudinally polarized electron or positron beam of HERA. Exclusive electroproduction of $\\omega$ mesons on unpolarized hydrogen and deuterium targets is studied in the kinematic region of $Q^2>1.0$ GeV$^2$, 3.0 GeV $< W <$ 6.3 GeV, and $-t'< 0.2 $ GeV$^{2}$, while for $\\rho^0$-meson production on a transversely polarized hydrogen target $-t'< 0.4$ GeV$^{2}$ is used. Spin-density matrix elements for $\\omega$ production are presented in projections of $Q^2$ or $-t'$, while the ratios of the helicity amplitudes for the reaction $\\gamma^*+p \\to \\rho^0+p$ are obtained in the entire kinematic region. The usage of the transversely polarized target allows for the first time the extraction of the ratios of certain nucleon-helicity-flip amplitudes to the natural-parity exchange amplitude $T_{0\\frac{1}{2}0\\frac{1}{2}}$ without the nucleon-helicity flip describing the longitudinal $\\rho^0$-meson production by the longitudinal...
Dynamical meson melting in holography
We discuss mesons in thermalizing gluon backgrounds in the N=2 supersymmetric QCD using the gravity dual. We numerically compute the dynamics of a probe D7-brane in the Vaidya-AdS geometry that corresponds to a D3-brane background thermalizing from zero to finite temperatures by energy injection. In static backgrounds, it has been known that there are two kinds of brane embeddings where the brane intersects the black hole or not. They correspond to the phases with melted or stable mesons. In our dynamical setup, we obtain three cases depending on final temperatures and injection time scales. The brane stays outside of the black hole horizon when the final temperature is low, while it intersects the horizon and settles down to the static equilibrium state when the final temperature is high. Between these two cases, we find the overeager case where the brane dynamically intersects the horizon although the final temperature is not high enough for a static brane to intersect the horizon. The interpretation of this phenomenon in the dual field theory is meson melting due to non-thermal effects caused by rapid energy injection. In addition, we comment on the late time evolution of the brane and a possibility of its reconnection
This talk deals with the author's recollections about the discoveries of the J/ψ the ψ' as well as psion spectroscopy and charmed mesons. He gives a chronology for the ψ and ψ' discoveries. He also discusses the events which led to the charmed meson discovery as well as detailed discussions on the proof that the resonance observed in the K- π+ system, at 1,865 MeV, was indeed the predicted charmed meson
Meson's Correlation Functions in a Nuclear Medium
Park, Chanyong
2016-01-01
We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the rho-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.
Gubler, Philipp; Lee, Su Houng; Oka, Makoto; Ozaki, Sho; Suzuki, Kei
2015-01-01
We investigate the mass spectra of open heavy flavor mesons in an external constant magnetic field within QCD sum rules. Spectral ans\\"atze on the phenomenological side are proposed in order to properly take into account mixing effects between the pseudoscalar and vector channels, and the Landau levels of charged mesons. The operator product expansion is implemented up to dimension--5 operators. As a result, we find for neutral D mesons a significant positive mass shift that goes beyond simple mixing effects. In contrast, charged D mesons are further subject to Landau level effects, which together with the mixing effects almost completely saturate the mass shifts obtained in our sum rule analysis.
Meson's correlation functions in a nuclear medium
Park, Chanyong
2016-09-01
We investigate meson's spectrum, decay constant and form factor in a nuclear medium through holographic two- and three-point correlation functions. To describe a nuclear medium composed of protons and neutrons, we consider a hard wall model on the thermal charged AdS geometry and show that due to the isospin interaction with a nuclear medium, there exist splittings of the meson's spectrum, decay constant and form factor relying on the isospin charge. In addition, we show that the ρ-meson's form factor describing an interaction with pseudoscalar fluctuation decreases when the nuclear density increases, while the interaction with a longitudinal part of an axial vector meson increases.
Photoproduction of vector mesons in nuclei
The mass of vector mesons in the nuclear medium is of great interest in strong interaction dynamics because vector meson masses could decrease with increasing baryonic density as a consequence of chiral symmetry restoration. The purpose of this work is to define an observable sensitive to vector meson masses at nuclear matter density. This short paper reports some preliminary results which suggest that the quantum interference between (e+e-) pairs emitted in the photoproduction of ρ- and ω- mesons near threshold in heavy nuclei could be such quantity. (J.S.). 4 refs., 2 figs
Single spin asymmetry for charm mesons
Dominguez Zacarias, G. [PIMAyC, Eje Central Lazaro Cardenas No. 152, Apdo. Postal 14-805, D.F. (Mexico); Herrera, G.; Mercado, J. [Centro de Investigacion y de Estudios Avanzados, Apdo. Postal 14-740, D.F. (Mexico)
2007-08-15
We study single spin asymmetries of D{sup 0} and D{sup -} mesons in polarized proton-proton collisions. A two component model is used to describe charm meson production. The production of D mesons occurs by recombination of the constituents present in the initial state as well as by fragmentation of quarks in the final state. This model has proved to describe the production of charm. The recombination component involves a mechanism of spin alignment that ends up in a single spin asymmetry. Experimental measurements of single spin asymmetry for pions at RHIC are compared with the model. Predictions for the asymmetry in D mesons are presented. (orig.)
Single spin asymmetry for charm mesons
We study single spin asymmetries of D0 and D- mesons in polarized proton-proton collisions. A two component model is used to describe charm meson production. The production of D mesons occurs by recombination of the constituents present in the initial state as well as by fragmentation of quarks in the final state. This model has proved to describe the production of charm. The recombination component involves a mechanism of spin alignment that ends up in a single spin asymmetry. Experimental measurements of single spin asymmetry for pions at RHIC are compared with the model. Predictions for the asymmetry in D mesons are presented. (orig.)
Strong decays of vector mesons to pseudoscalar mesons in the relativistic quark model
Ebert, D; Galkin, V O
2014-01-01
Strong decays of vector ($^3S_1$) mesons to the pair of pseudoscalar ($^1S_0$) mesons are considered in the framework of the microscopic decay mechanism and the relativistic quark model based on the quasipotential approach. The quark-antiquark potential, which was previously used for the successful description of meson spectroscopy and electroweak decays, is employed as the source of the $q\\bar q$ pair creation. The relativistic structure of the decay matrix element, relativistic contributions and boosts of the meson wave functions are comprehensively taken into account. The calculated rates of strong decays of light, heavy-light mesons and heavy quarkonia agree well with available experimental data.
η meson photoproduction on deuterium
Measurements of the total and differential cross sections for η-meson photoproduction on a D2 liquid target from threshold to 1.2 GeV, have been taken using the tagged Bremsstrahlung photon beam produced by the electrons extracted from the ELSA storage ring at Bonn. The reaction was identified by detecting the eta decay products in the neutral meson spectrometer SPES0-2π, while the recoil baryons (proton, neutron or deuteron) were detected by a variety of large angle scintillator detectors. We succeeded to identify completely the final states corresponding to the production of an η meson on a Quasi-Free (QF) proton, a QF neutron and the coherent deuteron. The differential cross sections corresponding to the production of a coherent deuteron n the final state have been measured, from threshold to 800 MeV; they are 6 times smaller the only previous measurement reported by Anderson and Prepost in 1969. This is consistent with an Isoscalar part of the Amplitude much smaller than the Isovector one. The differential cross sections are in good agreement with the theoretical prediction on the impulse approximation mechanism; indicating in particular, fairly small contributions from rescattering terms. A direct measurement of the neutron to proton cross section ratios has been obtained by integrating the counting rates on the corresponding QF peaks and is 0.70 ± 0.03, from 700 MeV to 900 MeV, with a small angular dependence. These two results by comparison to the measured free proton data should allow to reconstruct the free neutron cross sections in a rather model-independent way. (authors). 56 refs., 90 figs., 13 tabs
Heavy Mesons in Nuclear Matter and Nuclei
Tolos, Laura; Garcia-Recio, Carmen; Molina, Raquel; Nieves, Juan; Oset, Eulogio; Ramos, Angels; Romanets, Olena; Salcedo, Lorenzo Luis; Torres-Rincon, Juan M
2014-01-01
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI.
Heavy Mesons in Nuclear Matter and Nuclei
Heavy mesons in nuclear matter and nuclei are analyzed within different frameworks, paying a special attention to unitarized coupled-channel approaches. Possible experimental signatures of the properties of these mesons in matter are addressed, in particular in connection with the future FAIR facility at GSI
Experimental evidence for hadroproduction of exotic mesons
New measurements of peripheral meson production are presented. The data confirm the existence of exotic mesons at 1.4 and 1.6 GeV/c2. The latter state dominates the eta'pi- decay spectrum. The data on eta pi+pi-pi- decay show large strength in several exotic (Jpc = 1- +) waves as well
New results of radiative meson decays
We have investigated Coulomb dissociation (the Primakoff effect) of high energy charged r and K mesons on heavy nuclei. New values for the electromagnetic transition rates G(p-→rg) and G(K-→K-g) have been extracted from the data. Some preliminary data for the Primakoff production of higher meson excitations will also be presented
Pseudotensor mesons as three-body resonances
Roca, L
2011-01-01
We show that the lightest pseudotensor mesons J^{PC}=2^-+ can be regarded as molecules made of a pseudoscalar (P) 0^-+ and a tensor 2^++ meson, where the latter is itself made of two vector (V) mesons. The idea stems from the fact that the vector-vector interaction in s-wave and spin 2 is very strong, to the point of generating the 2^++ tensor mesons. On the other hand the interaction of a pseudoscalar with a vector meson in s-wave is also very strong and it generates dynamically the lightest axial-vector mesons. Therefore we expect the PVV interaction to be strongly attractive and thus able to build up quasibound PVV resonances. We calculate the three body PVV interaction by using the fixed center approximation to the Faddeev equations where the two vectors are clustered forming a tensor meson. We find clear resonant structures which can be identified with the pi_2(1670), eta_2(1645) and K^*_2(1770) (2^-+) pseudotensor mesons.
Scalar and axial-vector mesons
Van Beveren, E; Beveren, Eef van; Rupp, George
2007-01-01
Nowadays, there exists an abundance of theoretical approaches towards the mesonic spectrum, ranging from confinement models of all kinds, i.e., glueballs, and quark-antiquark, multiquark and hybrid configurations, to models in which only mesonic degrees of freedom are taken into account. Nature seems to come out somewhere in the middle, neither preferring pure bound states, nor effective meson-meson physics with only coupling constants and possibly form factors. As a matter of fact, apart from a few exceptions, like pions and kaons, Nature does not allow us to study mesonic bound states of any kind, which is equivalent to saying that such states do not really exist. Hence, instead of extrapolating from pions and kaons to the remainder of the meson family, it is more democratic to consider pions and kaons mesonic resonances that happen to come out below the lowest threshold for strong decay. Nevertheless, confinement is an important ingredient for understanding the many regularities observed in mesonic spectra...
Sigma meson in heavy ion collision
We want to present a short theoretical prediction of the behaviour of the sigma meson in heavy ion collisions. It is considered that the sigma meson is a pion-pion correlation, resulting from the decay of the N*(1440) resonance. There will be presented some QMD simulations. (authors)
Studies of Excited $D$ mesons in $B$ meson decays
AUTHOR|(CDS)2082679
This thesis documents the studies of several three-body B + meson decays, each with a charged charmed meson in the final state. All analyses presented use a data sample recorded by the LHCb detector in 2011 and 2012, corresponding to an integrated luminosity of 3.0 $fb^{-1}$ of $pp$ collision data. The $B^{+} \\to D^{-}K^{+}\\pi^{+}$ and $B^{+} \\to D^{+}K^{+}\\pi^{-}$ decay modes are observed for the first time. The branching fraction of the favoured $B^{+} \\to D^{-}K^{+}\\pi^{+}$ decay mode is measured relative to the topologically similar $B^{+} \\to D^{-}\\pi^{+}\\pi^{+}$ decay and the $B^{+} \\to D^{-}K^{+}\\pi^{+}$ final state is used as a normalisation channel for the suppressed $B^{+} \\to D^{+}K^{+}\\pi^{-}$ decay branching fraction measurement. Searches are performed for the quasi-two-body decays $B^{+} \\to D^{+}K^{*}(892)^{0}$ and $B^{+} \\to D_{2}^{*}(2460)^{0}K^{+}$, using the sample of $B^{+} \\to D^{+}K^{+}\\pi^{-}$ candidate decays. No significant signals are observed for either decay mode and upper limits a...
Light meson radial Regge trajectories
Badalian, A.M.; Bakker, B. L. G.; Simonov, Yu. A.
2002-01-01
A new physical mechanism is suggested to explain the universal depletion of high meson excitations. It takes into account the appearance of holes inside the string world sheet due to $q\\bar{q}$ pair creation when the length of the string exceeds the critical value $R_1 \\simeq 1.4$ fm. It is argued that a delicate balance between large $N_c$ loop suppression and a favorable gain in the action, produced by holes, creates a new metastable (predecay) stage with a renormalized string tension which...
ν' meson as pseudoscalar gluonium
The problem of the ν' meson as a pseudoscalar gluonium within the systematic approach to the resonance physics is considered. QCD sum rules induced by the current Gsub(μν)sup(α)Gsub(μν)sup(α) tilde constructed form gluon field operators are derived. By saturating the sum rules the ν' rough estimates fro the ν' mass and its residue are given. The difference between the ν' and typical quark states such as the rho is noted. Breaking of the operator expansion by the instanton effects is discussed
Status of chiral meson physics
Bijnens, Johan [Department of Astronomy and Theoretical Physics, Lund University, Sölvegatan 14A, SE 22362 Lund (Sweden)
2016-01-22
This talk includes a short introduction to Chiral Perturbation Theory in the meson sector concentrating on a number of recent developments. I discuss the latest fit of the low-energy constants. Finite volume corrections are discussed for the case with twisted boundary conditions for form-factors and first results at two-loops for three flavours for masses. The last part discusses the extension to other symmetry breaking patterns relevant for technicolour and related theories as well as the calculation of leading logarithms to high loop orders.
Results for light pseudoscalar mesons
Bazavov, A; DeTar, C; Du, X; Freeman, W; Gottlieb, Steven; Heller, Urs M; Hetrick, J E; Laiho, J; Levkova, L; Oktay, M B; Osborn, J; Sugar, R; Toussaint, D; Van de Water, R S
2010-01-01
We present the current status of the MILC collaboration's calculations of the properties of the light pseudoscalar meson sector. We use asqtad staggered ensembles with 2+1 dynamical flavors down to $a \\approx 0.045$ fm and light quark mass down to 0.05 $m_s$. Here we describe fits to the data using chiral forms from SU(3) chiral perturbation theory, including all staggered taste violations at NLO and the continuum NNLO chiral logarithms. We emphasize issues of convergence of the chiral expansion.
Vector meson mixing and charge symmetry violation
We discuss the consistency of the traditional vector meson dominance (VMD) model for photons coupling to matter with the vanishing of vector meson-meson- and meson-photon mixing self-energies at q2 = O. This vanishing of vector mixing has been demonstrated in the context of rho-omega mixing for a large class of effective theories. As a further constraint on these models, we here apply them to a study of photon-meson mixing and VMD. We compare the predicted momentum dependence of two models with that extracted experimentally. We find that one model produces a momentum-dependence which is consistent with the data, while the other does not. Hence we conclude that comparison with VMD phenomenology provides a powerful constraint on such models. (author). 34 refs., 1 fig
D-meson diffusion in hadronic matter
We present effective-field-theory results with unitarized interactions on the D-meson transport coefficients in a gas populated by light mesons and baryons at finite temperature and baryochemical potential. The Fokker-Planck equation is used to compute the drag force, the relaxation time and the diffusion coefficients of D mesons for collisions at FAIR. At finite baryochemical potential, the combined effect of net baryonic density and sizable meson-baryon interaction makes the D mesons to relax more efficiently than in the μB = 0 case. We also describe the connection with the quark-gluon plasma phase in adiabatic trajectories on the phase diagram at both zero and finite baryochemical potential.
Light Vector Mesons in the Nuclear Medium
Wood, Michael; Nasseripour, Rakhsha; Weygand, Dennis; Djalali, Chaden; Tur, Clarisse; Mosel, Ulrich; Muehlich, Pascal; Adams, Gary; Amaryan, Moscov; Amaryan, Moskov; Ambrozewicz, Pawel; Anghinolfi, Marco; Asryan, Gegham; Avagyan, Harutyun; Baghdasaryan, Hovhannes; Baillie, Nathan; Ball, James; Baltzell, Nathan; Barrow, Steve; Battaglieri, Marco; Bedlinskiy, Ivan; Bektasoglu, Mehmet; Bellis, Matthew; Benmouna, Nawal; Berman, Barry; Biselli, Angela; Blaszczyk, Lukasz; Bouchigny, Sylvain; Boyarinov, Sergey; Bradford, Robert; Branford, Derek; Briscoe, William; Brooks, William; Burkert, Volker; Butuceanu, Cornel; Calarco, John; Careccia, Sharon; Carman, Daniel; Carnahan, Bryan; Casey, Liam; Chen, Shifeng; Cheng, Lu; Cole, Philip; Collins, Patrick; Coltharp, Philip; Crabb, Donald; Crannell, Hall; Crede, Volker; Cummings, John; Dashyan, Natalya; De Vita, Raffaella; De Sanctis, Enzo; Degtiarenko, Pavel; Denizli, Haluk; Dennis, Lawrence; Deur, Alexandre; Dharmawardane, Kahanawita; Dickson, Richard; Dodge, Gail; Doughty, David; Dugger, Michael; Dytman, Steven; Dzyubak, Oleksandr; Egiyan, Hovanes; Egiyan, Kim; Elfassi, Lamiaa; Elouadrhiri, Latifa; Eugenio, Paul; Fedotov, Gleb; Feldman, Gerald; Feuerbach, Robert; Fradi, Ahmed; Funsten, Herbert; Garcon, Michel; Gavalian, Gagik; Gilfoyle, Gerard; Giovanetti, Kevin; Girod, Francois-Xavier; Goetz, John; Gordon, Christopher; Gothe, Ralf; Griffioen, Keith; Guidal, Michel; Guler, Nevzat; Guo, Lei; Gyurjyan, Vardan; Hadjidakis, Cynthia; Hafidi, Kawtar; Hakobyan, Hayk; Hakobyan, Rafael; Hanretty, Charles; Hardie, John; Hassall, Neil; Hersman, F.; Hicks, Kenneth; Hleiqawi, Ishaq; Holtrop, Maurik; Hyde, Charles; Ilieva, Yordanka; Ireland, David; Ishkhanov, Boris; Isupov, Evgeny; Ito, Mark; Jenkins, David; Jo, Hyon-Suk; Johnstone, John; Joo, Kyungseon; Juengst, Henry; Kalantarians, Narbe; Kellie, James; Khandaker, Mahbubul; Khetarpal, Puneet; Kim, Wooyoung; Klein, Andreas; Klein, Franz; Klimenko, Alexei; Kossov, Mikhail; Krahn, Zebulun; Kramer, Laird; Kubarovsky, Valery; Kuhn, Joachim; Kuhn, Sebastian; Kuleshov, Sergey; Lachniet, Jeff; Laget, Jean; Langheinrich, Jorn; Lawrence, David; Li, Ji; Livingston, Kenneth; Lu, Haiyun; MacCormick, Marion; Markov, Nikolai; Mattione, Paul; McAleer, Simeon; McKinnon, Bryan; McNabb, John; Mecking, Bernhard; Mehrabyan, Surik; Melone, Joseph; Mestayer, Mac; Meyer, Curtis; Mibe, Tsutomu; Mikhaylov, Konstantin; Minehart, Ralph; Mirazita, Marco; Miskimen, Rory; Mokeev, Viktor; Moriya, Kei; Morrow, Steven; Moteabbed, Maryam; Mueller, James; Munevar Espitia, Edwin; Mutchler, Gordon; Nadel-Turonski, Pawel; Niccolai, Silvia; Niculescu, Gabriel; Niculescu, Maria-Ioana; Niczyporuk, Bogdan; Niroula, Megh; Niyazov, Rustam; Nozar, Mina; Osipenko, Mikhail; Ostrovidov, Alexander; Park, Kijun; Pasyuk, Evgueni; Paterson, Craig; Pereira, Sergio; Pierce, Joshua; Pivnyuk, Nikolay; Pocanic, Dinko; Pogorelko, Oleg; Pozdnyakov, Sergey; Preedom, Barry; Price, John; Prok, Yelena; Protopopescu, Dan; Raue, Brian; Riccardi, Gregory; Ricco, Giovanni; Ripani, Marco; Ritchie, Barry; Ronchetti, Federico; Rosner, Guenther; Rossi, Patrizia; Sabatie, Franck; Salamanca, Julian; Salgado, Carlos; Santoro, Joseph; Sapunenko, Vladimir; Schumacher, Reinhard; Serov, Vladimir; Sharabian, Youri; Sharov, Dmitri; Shvedunov, Nikolay; Smith, Elton; Smith, Lee; Sober, Daniel; Sokhan, Daria; Stavinsky, Aleksey; Stepanyan, Stepan; Stepanyan, Samuel; Stokes, Burnham; Stoler, Paul; Strakovski, Igor; Strauch, Steffen; Taiuti, Mauro; Tedeschi, David; Tkabladze, Avtandil; Tkachenko, Svyatoslav; Todor, Luminita; Ungaro, Maurizio; Vineyard, Michael; Vlassov, Alexander; Watts, Daniel; Weinstein, Lawrence; Williams, Michael; Wolin, Elliott; Yegneswaran, Amrit; Zana, Lorenzo; Zhang, Bin; Zhang, Jixie; Zhao, Bo; Zhao, Zhiwen
2008-07-01
The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body eff
Strange and charm mesons at FAIR
Tolos, L; Gamermann, D; Garcia-Recio, C; Molina, R; Nieves, J; Oset, E; Ramos, A
2009-01-01
We study the properties of strange and charm mesons in hot and dense matter within a self-consistent coupled-channel approach for the experimental conditions of density and temperature expected for the CBM experiment at FAIR/GSI. The in-medium solution at finite temperature accounts for Pauli blocking effects, mean-field binding of all the baryons involved, and meson self-energies. We analyze the behaviour in this hot and dense environment of dynamically-generated baryonic resonances together with the evolution with density and temperature of the strange and open-charm meson spectral functions. We test the spectral functions for strange mesons using energy-weighted sum rules and finally discuss the implications of the properties of charm mesons on the D_{s0}(2317) and the predicted X(3700) scalar resonances.
Dobado, A; Dobado, Antonio; Llanes-Estrada, Felipe J.
2003-01-01
We report a calculation of the shear viscosity in a relativistic multicomponent meson gas as a function of temperature and chemical potentials. We approximately solve the Uehling-Uhlenbeck transport equation of kinetic theory, appropriate for a boson gas, with relativistic kinematics. Since at low temperatures the gas can be taken as mostly composed of pions, with a fraction of kaons and etas, we explore the region where binary elastic collisions with at least one pion are the dominant scattering processes. Our input meson scattering phase shifts are fits to the experimental data obtained from chiral perturbation theory and the Inverse Amplitude Method. Our results take the correct non-relativistic limit (viscosity proportional to the square root of the temperature), show a viscosity of order the cubed of the pion mass up to temperatures somewhat below that mass, and then a large increase due to kaons and etas. Our approximation may break down at even higher temperatures, where the viscosity follows a tempera...
Mesons in relativistic quark model
In the relativistic quark model formulated in the infinite momentum frame a self-consistent description has been obtained for a pion, ω- and ρ-mesons, K- and K*-mesons. The role of the relativistic effects in the description of radiative, leptonic and semileptonic decays of heavy quarkonia is studied. The relativistic effects are shown to lead to noticeable suppression of the ψ → ηcγ decay width predicted in nonrelativistic approximation; however the discrepancy with the experimental data still remains. Predictions are obtained for amplitudes of D → μν, Ds → μν, B → μν, D → πeν and D → Keν decays. The relativistic effects are shown to lead to strong supperssion of coupling constants of D → μν, Ds → μν, B → μν decays. The prediction obtained for the coupling constant FD = 230-270 MeV is close to the boundary of available experimental restriction. 46 refs.; 2 figs.; 5 tabs
Pseudocalar meson and vector meson interactions and dynamically generated axial-vector mesons
Zhou, Yu; Ren, Xiu-Lei; Chen, Hua-Xing; Geng, Li-Sheng
2014-01-01
The axial-vector mesons $a_1(1260)$, $b_1(1235)$, $f_1(1285)$, $h_1(1170)$, $h_1(1380)$, and $K_1(1270)$ are dynamically generated in the unitized chiral perturbation theory. Such a picture has been tested extensively in the past few years. In this work, we calculate the interaction kernel up to $\\mathcal{O}(p^2)$ and study the impact on the dynamically generated axial-vector states. In anticipation of future lattice QCD simulations, we calculate the scattering lengths and the pole positions ...
Strong Couplings of Three Mesons with Charm(ing) Involvement
Lucha, Wolfgang; Sazdjian, Hagop; Simula, Silvano
2016-01-01
We determine the strong couplings of three mesons that involve, at least, one $\\eta_c$ or $J/\\psi$ meson, within the framework of a constituent-quark model by means of relativistic dispersion formulations. For strong couplings of $J/\\psi$ mesons to two charmed mesons, our approach leads to predictions roughly twice as large as those arising from QCD sum rules.
Distortion of the HBT images by meson clouds
Hattori, K
2009-01-01
We study the effects of mesonic final state interactions on the Hanbury Brown and Twiss (HBT) intensity interferometry for mesons in ultra-relativistic heavy ion collisions. Modification of the one-body amplitude of emitted mesons while going through a cloud of other mesons is estimated in the semiclassical approximation with a mesonic optical potential which incorporates both coherent forward scattering with other mesons and the absorption due to the incoherent scattering in the meson clouds. We show how these effects results in the distortion of the HBT images.
Exclusive φ meson production in HERMES
Golembiovskaya, Mayya
2014-03-15
In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U{sub 1}, U{sub 2} and U{sub 3} which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q{sup 2}, 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.
Exclusive φ meson production in HERMES
In the present work exclusive φ meson leptoproduction at HERMES experiment in DESY was studied using the data collected at HERA accelerator in the period from 1998 till 2000 and from 2006 till 2007 years. In the analysis unpolarized and longitudinally polarized hydrogen and deuteron targets were used, the beam consisted of longitudinally polarized leptons. Via measurement of the angular and momentum distribution of the φ meson decay products 23 spin density matrix elements (SDMEs) for the φ meson were obtained. The number of SDMEs was defined by the experiment conditions, e.g. by the beam and target polarization directions. For the mentioned time period φ meson SDMEs were defined at HERMES for the first time. The quantities U1, U2 and U3 which can be used to check presence of unnatural parity exchange (UPE) mechanism in phi meson production were calculated from SDMEs. All the results were obtained in 3 kinematic bins of Q2, 4 kinematic bins of t' and for the integrated kinematics. No statistically significant difference between the results for hydrogen and deuteron targets was observed. The UPE quantities were found to be zero within 2 σ for the integrated kinematics, indicating negligible contribution of UPE for the φ meson production which is in agreement with theory predictions. The test of s-channel helicity conservation hypothesis via comparison of corresponding SDME values showed helicity conservation for the φ meson production.
GlueX: Meson Spectroscopy in Photoproduction
Salgado, Carlos [Norfolk State University, JLAB; Smith, Elton S. [JLAB
2014-03-01
The goal of the GlueX experiment \\cite{gluex} is to provide crucial data to help understand the soft gluonic fields responsible for binding quarks in hadrons. Hybrid mesons, and in particular exotic hybrid mesons, provide the ideal laboratory for testing QCD in the confinement regime since these mesons explicitly manifest the gluonic degrees of freedom. Photoproduction is expected to be effective in producing exotic hybrids but there is little data on the photoproduction of light mesons. GlueX will use the new 12-GeV electron beam at Jefferson Lab to produce a 9-GeV beam of linearly polarized photons using the technique of coherent bremsstrahlung. A solenoid-based hermetic detector is under construction, which will be used to collect data on meson production and decays. These data will also be used to study the spectrum of conventional mesons, including the poorly understood excited vector mesons. This talk will give an update on the experiment as well as describe theoretical developments \\cite{Dudek:2011bn} to help understand how these data can provide insights into the fundamental theory of strong interactions.
Quantum field theory approaches to meson structure
Meson spectroscopy became one of the most interesting topics in particle physics in the last ten years. In particular, the discovery of new unexpected states in the charmonium spectrum which cannot be simply explained by the constituent quark model attracted the interest of many theoretical efforts. In the present thesis we discuss different meson structures ranging from light and heavy quark-antiquark states to bound states of hadrons-hadronic molecules. Here we consider the light scalar mesons f0(980) and a0(980) and the charmonium-like Y(3940), Y(4140) and Z±(4430) states. In the discussion of the meson properties like mass spectrum, total and partial decay widths and production rates we introduce three different theoretical methods for the treatment and description of hadronic structure. For the study of bound states of mesons we apply a coupled channel approach which allows for the dynamical generation of meson-meson resonances. The decay properties of meson molecules are further on studied within a second model based on effective Lagrangians describing the interaction of the bound state and its constituents. Besides hadronic molecules the effective Lagrangian approach is also used to study the radiative and strong decay properties of ordinary quark-antiquark (q anti q) states. The AdS/QCD model forms the completion of the three theoretical methods introduced in the present thesis. This holographic model provides a completely different ansatz and is based on extra dimensions and string theory. Within this framework we calculate the mass spectrum of light and heavy mesons and their decay constants.
Search for radiative B meson decays
The Crystal Ball detector at the ε+ε- storage ring DORIS-II has been used to search for radiative B meson decays, especially of the type b→sγ. No mono-energetic γ-lines have been found in the inclusive photon spectrum from Υ(4S) decays, and upper limits are obtained for radiative decays of B mesons to various strange mesons and to the D*. Integrating the photon spectrum over the corresponding energy range, we find BR(B→γX)-3 at 90% confidence level for the mass range 892 MeV≤MX≤2045 MeV. (orig.)
We study the flavour singlet pseudoscalar mesons from first principles using lattice QCD. With Nf=2 flavours of light quark, this is the so-called η2 meson and we discuss the phenomenological status of this. Using maximally twisted-mass lattice QCD, we extract the mass of the η2 meson at two values of the lattice spacing for lighter quarks than previously discussed in the literature. We are able to estimate the mass value in the limit of light quarks with their physical masses. (orig.)
Meson facility. Powerful new research tool
A meson facility is being built at the Institute of Nuclear Research, USSR Academy of Sciences, in Troitsk, where the Scientific Center, USSR Academy of Sciences is located. The facility will include a linear accelerator for protons and negative hydrogen ions with 600 MeV energy and 0.5-1 mA beam current. Some fundamental studies that can be studied at a meson facility are described in the areas of elementary particles, neutron physics, solid state physics, and applied research. The characteristics of the linear accelerator are given and the meson facility's experimental complex is described
Recent progress on light scalar mesons
Peláez Sagredo, José Ramón
2014-01-01
This is a brief account of the recent developments on the determination of the mass and widths of the much debated scalar mesons, paying particular attention to the causes of major revision of the σ or f_0(500) meson in the last edition of the Review of Particle Physics, which has finally acknowledged that the situation concerning the mass and width of this controversial state has been settled, although this was already well-known to scalar meson practitioners for about a decade. I will brief...
Measurement of the B0-meson lifetime
We report a measurement of the lifetime of the B0 meson based upon 29-GeV e+e- annihilation data taken with the Mark II detector at the SLAC storage ring PEP. The B0 mesons are tagged by their decays into D*-e+ν and D*-μ+ν, where the D*- is tagged by its decay into π-bar D0. We reconstruct the decay vertices of 15 B0-meson candidates and measure the B0 lifetime to be 1.20+0.52-0.36+0.160.14 psec
Bottom-strange mesons in hyperonic matter
Pathak, Divakar; Mishra, Amruta
2014-01-01
The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of t...
Weak decays of the Bc meson to Bs and B mesons in the relativistic quark model
Semileptonic and non-leptonic decays of the Bc meson to Bs and B mesons, caused by the c→s,d quark transitions, are studied in the framework of the relativistic quark model. The heavy quark expansion in inverse powers of the active c and spectator anti b quark is used to simplify calculations while the final s and d quarks in the Bs and B mesons are treated relativistically. The decay form factors are explicitly expressed through the overlap integrals of the meson wave functions in the whole accessible kinematical range. The obtained results are compared with the predictions of other approaches. (orig.)
Tetraquarks in the 1/N expansion and meson-meson resonances
Maiani, L; Riquer, V.
2016-01-01
Diquarks are found to have the right degrees of freedom to describe the tetraquark poles in hidden-charm to open-charm meson-meson amplitudes. Compact tetraquarks result as intermediate states in non-planar diagrams of the 1/N expansion and the corresponding resonances are narrower than what estimated before. The proximity of tetraquarks to meson-thresholds has an apparent role in this analysis and, in the language of meson molecules, an halving rule in the counting of states is obtained.
Modified meson-nucleus optical potentials
Wilkin, C
1973-01-01
The author argues that the energy dependence of the meson-nucleus optical potential should be treated in a more dynamical fashion. When this is done, some of the difficulties found in phenomenological applications are eliminated. (13 refs).
(→ + - 0) meson photoproduction on proton
Swapan Das
2010-10-01
The cross-section for the + - 0 invariant mass distribution in the $ p$ reaction in the GeV region is calculated. This reaction is assumed to proceed through the formation of the -meson in the intermediate state, because the production cross-section for this meson in the reaction in the GeV region is significant and it has a large branching ratio (88.8%) in the + − 0 channel. The cross-sections for this reaction are calculated using the energy-dependent reaction amplitude, → (0), extracted from the latest -meson photoproduction data. We use established procedure to calculate other factors, like width and propagator of the -meson, so that our calculation can provide reliable cross-section. The calculated results reproduce the measured + - 0 invariant mass distribution spectra in the reaction.
Kaons in flavor tagged B meson decays
Using the ARGUS detector at the e+e- storage ring DORIS II, measurements of multiplicities of pseudoscalar kaons, of K*(892) and of φ(1020) in B meson decays have been performed through studies of angular and charge correlations between the above particles and high momentum leptons produced in semileptonic B decays. The method has made it possible to measure the multiplicities separately for B-mesons and anti-B-mesons. The excess of like charge lepton-kaon pairs over opposite charge pairs in semileptonic decays was used for estimating the ratio of charmed decays over all decays, and thus also the fraction of charmless decays. A search for an excess of fast neutral kaons from rare B decays was also made. All the results obtained support the assumption that almost all B mesons decay through b → c transitions into charmed hadrons. (66 refs.)
Atoms and mesons. Atomy i mezony
Kirillov-Ygryumov, V.G.; Nikitin, Yu.P.; Sergeev, F.M.
1980-01-01
A study is made of interactions between muons and hadrons and matter. Investigations are made of hadron-nuclear and lepton-nuclear interactions in the energy range that is characteristic of meson factories (up to 200 MeV). Considerable attention is given to meson and nuclear interactions in the bound state as well as to nuclear capture of mesons. An examination is made of the formation of high-energy and ..mu..-nucleon atoms, elastic and inelastic meson scattering on nuclei, the connection between scattering processes and mesoatoms, and their role in the structural analysis of nuclei and elementary particles. A phase analysis is made of experimental results for elastic scattering on nucleons and nuclei. The book is intended for scientists specializing in the physics of low energies. It might also be used by graduate and senior undergraduate students majoring in physics and physical engineering. 103 references, 31 figures, 18 tables.
Photo and electroproduction of heavy mesons
This report reviews first the η0 photoproduction then the photoproduction vector mesons and presents some results. Finally, some notes on the experimental devices which should have to be developed to undertake this study are given
Quasinormal modes and meson decay rates
Hoyos, C. [Department of Physics, University of Wales Swansea, Swansea, SA2 8PP (United Kingdom); Landsteiner, K.; Montero, S. [Instituto de Fisica Teorica, C-XVI Universidad Autonoma de Madrid, 28049 Madrid (Spain)
2007-05-15
We model meson melting in a hot plasma by the quasinormal modes of D7-brane fluctuations of embeddings that fall into the horizon of a black hole in Ads{sub 5} x S{sup 5} geometry. The inverse of the imaginary part of the quasinormal frequency gives the lifetime of the meson in the plasma. We briefly comment on the possible application of our model to quarkonium suppression. (Abstract Copyright [2007], Wiley Periodicals, Inc.)
Quasinormal modes and meson decay rates
We model meson melting in a hot plasma by the quasinormal modes of D7-brane fluctuations of embeddings that fall into the horizon of a black hole in Ads5 x S5 geometry. The inverse of the imaginary part of the quasinormal frequency gives the lifetime of the meson in the plasma. We briefly comment on the possible application of our model to quarkonium suppression. (Abstract Copyright [2007], Wiley Periodicals, Inc.)
Meson condensation in dense matter revisited
Yabu, H; Kubodera, K; Yabu, Hiroyuki
1994-01-01
The results for meson condensation in the literature vary markedly depending on whether one uses chiral perturbation theory or the current-algebra-plus-PCAC approach. To elucidate the origin of this discrepancy, we re-examine the role of the sigma-term in meson condensation. We find that the resolution of the existing discrepancy requires a knowledge of terms in the Lagrangian that are higher order in density than hitherto considered.
THE ETA-MESON PHOTOPRODUCTION ON PROTON
Donoval, Jan; Bydžovský, Petr
2011-01-01
Roč. 26, 3-4 (2011), s. 645-646. ISSN 0217-751X. [11th International Workshop on Meson Production, Properties and Interaction. Krakow, 10.06.2010-15.06.2010] R&D Projects: GA ČR GA202/08/0984 Institutional research plan: CEZ:AV0Z10480505 Keywords : Eta-meson photoproduction * form factors * nucleon resonances Subject RIV: BG - Nuclear, Atomic and Molecular Physics , Colliders Impact factor: 1.053, year: 2011
Rare meson decays into very light neutralinos
O'Leary, Ben
2009-01-01
Results are presented for the two-body decays of mesons into light neutralinos and from the first complete calculation of the loop-induced decays of kaons to pions plus light neutralinos and of B mesons to kaons plus light neutralinos. The branching ratios are shown to be strongly suppressed within the MSSM with minimal flavor violation, and no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed.
A light exotic qantiqg hermaphrodite meson
It is suggested that qantiqg mesons may exist as low as 1Gev in mass. The exotic Jsup(PC)=1-+ multiplet will have distinctive decay modes and perhaps be relatively stable. The bag model spectrum of the lowest lying qantiqg multiplet including hyperfine splittings is computed analogously to Jaffe's (Phys. Lett.; 60B:201 (1976)) qantiqqantiq bag model multiplets. Relevance to light meson phenomenology is discussed. (author)
Oscillations of neutral B mesons systems
Boucrot, J.
1999-01-01
The oscillation phenomenon in the neutral B mesons systems is now well established. The motivations and principles of the measurements are given; then the most recent results from the LEP experiments, the CDF collaboration at Fermilab and the SLD collaboration at SLAC are reviewed. The present world average of the $\\bd$ meson oscillation frequency is $\\dmd = 0.471 \\pm 0.016 \\ps$ and the lower limit on the $\\bs$ oscillation frequency is $\\dms > 12.4 \\ps at 95% CL$.
Meson and baryon spectroscopy on the lattice
David Richards
2010-12-01
Recent progress at understanding the excited state spectrum of mesons and baryons is described. I begin by outlining the application of the variational method to compute the spectrum, and the program of anisotropic clover lattice generation designed for hadron spectroscopy. I present results for the excited meson spectrum, with continuum quantum numbers of the states clearly delineated. I conclude with recent results for the low lying baryon spectrum, and the prospects for future calculations.
The interactions of heavy mesons with nuclei
Data obtained from interactions of heavy mesons with nuclei is reviewed. Nucleon-nucleon reactions followed by p + d (or d+p) reactions and nucleon-nucleus reactions are described. A meson decay experiment is discussed. The fundamental importance of S11 (1535) in η-nucleon is stressed. The propagation of resonances through nuclear matter is considered. Improvements in this research field require the developement of a new accelerator generation
Potential for discoveries in charm meson physics
The possibility of using charm meson physics to test the Standard Model (SM) is reviewed. In the case of D0-bar D0 mixing, the SM contributions are carefully considered and the existence of a window for the observation of new physics is discussed. Some examples of extensions of the SM giving large mixing signals are presented. Finally, some distinctive aspects of CP violation and rare decays in charm mesons are discussed. copyright 1996 American Institute of Physics
Bs mesons: semileptonic and nonleptonic decays
Albertus C.
2014-01-01
Full Text Available In this contribution we compute some nonleptonic and semileptonic decay widths of Bs mesons, working in the context of constituent quark models [1, 2]. For the case of semileptonic decays we consider reactions leading to kaons or different Jπ Ds mesons. The study of nonleptonic decays has been done in the factorisation approximation and includes the final states enclosed in Table 2.
Beautiful mesons from QCD spectral sum rules
Narison, S. (OPM, Univ. Montpellier 2, 34 (France))
1991-08-01
We discuss the beautiful meson from the point of view of the QCD spectral sum rules (QSSR). The bottom quark mass and the mixed light quark-gluon condensates are determined quite accurately. The decay constant f{sub B} is estimated and we present some arguments supporting this result. The decay constants and the masses of the other members of the beautiful meson family are predicted. (orig.).
Light $O^{++}$ Mesons: Scalargators in Florida
Pennington, M. R.
2010-01-01
Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment a...
Meson Condensation in Dense Matter Revisited
Yabu, Hiroyuki; Myhrer, F.; Kubodera, K.
1994-01-01
The results for meson condensation in the literature vary markedly depending on whether one uses chiral perturbation theory or the current-algebra-plus-PCAC approach. To elucidate the origin of this discrepancy, we re-examine the role of the sigma-term in meson condensation. We find that the resolution of the existing discrepancy requires a knowledge of terms in the Lagrangian that are higher order in density than hitherto considered.
Exotic mesons in quenched lattice QCD
Bernard, C W; DeTar, C E; Gottlieb, S; Heller, U M; Hetrick, J E; McNeile, C; Rummukainen, K; Sugar, B; Toussaint, D; Wingate, M; Bernard, Claude; Grand, Thomas A. De; Tar, Carleton De; Gottlieb, Steven; Heller, Urs M.; Hetrick, James E.; Neile, Craig Mc; Rummukainen, Kari; Sugar, Bob; Toussaint, Doug; Wingate, Matthew
1997-01-01
Since gluons in QCD are interacting fundamental constituents just as quarks are, we expect that in addition to mesons made from a quark and an antiquark, there should also be glueballs and hybrids (bound states of quarks, antiquarks and gluons). In general, these states would mix strongly with the conventional q-bar-q mesons. However, they can also have exotic quantum numbers inaccessible to q-bar-q mesons. Confirmation of such states would give information on the role of "dynamical" color in low energy QCD. In the quenched approximation we present a lattice calculation of the masses of mesons with exotic quantum numbers. These hybrid mesons can mix with four quark (q-bar-q-bar-q-q) states. The quenched approximation partially suppresses this mixing. Nonetheless, our hybrid interpolating fields also couple to four quark states. Using a four quark source operator, we demonstrate this mixing for the 1-+ meson. Using the conventional Wilson quark action, we calculate both at reasonably light quark masses, intend...
Spectroscopy of mesonic molecules with heavy-light flavour mesons
Rathaud, D P
2016-01-01
In this work, we have calculated the mass spectra and decay properties of dimesonic (meson-antimeson) bound state in the variational scheme. The intermesonic interaction considered as the Hellmann potential and One Pion Exchange potential. The mass spectra of the $D\\bar{D^{*}}$, $D\\bar{D_{s}^{*}}$, $D_{s}\\bar{D^{*}}$, $D_{s}\\bar{D_{s}^{*}}$, $D^{*}\\bar{D^{*}}$, $D_{s}^{*}\\bar{D_{s}^{*}}$, $D\\bar{B^{*}}$, $D\\bar{B_{s}^{*}}$, $D_{s}\\bar{B^{*}}$, $D_{s}\\bar{B_{s}^{*}}$, $B^{*}\\bar{D}$,$B^{*}\\bar{D_{s}}$, $B\\bar{B^{*}}$, $B_{s}\\bar{B^{*}}$, $B_{c}\\bar{B^{*}}$, $B^{*}\\bar{B^{*}}$, $B^{*}\\bar{B_{s}^{*}}$, $B_{s}^{*}\\bar{B_{s}^{*}}$ etc.. are calculated. The states X(3872), $X_{2c}(4013)$ ,$Z_{b}(10610)/X_{b}$ and $Z_{b}(10650)/X_{b2}$ are compared with $D\\bar{D^{*}}$, $D^{*}\\bar{D^{*}}$, $B\\bar{B^{*}}$ and $B^{*}\\bar{B^{*}}$ dimesonic bound states. To probe the molecular structure of the compared states, we have calculated the decay properties sensitive to their long and short distance structure of hadorinc molecul...
Since the discovery of the upsilon resonances in 1977 the physics of the fifth quark - beauty - has played a vital role in establishing and consolidating today's Standard Model of particle physics. In recent years, a wealth of data on B particle (containing the beauty quark) has emerged from the detectors ARGUS (at the DORIS ring, DESY, Hamburg) and CLEO (at the Cornell CESR ring) as well as from CERN's LEP electron-positron collider and the proton-antiproton colliders at CERN and Fermilab. But the most challenging goal of this physics is to explore the mystery of CP violation, so far only seen in neutral kaon decays. This subtle mechanism - a disregard for the combined symmetry of particle antiparticle switching and left-right reflection - possibly moulded the evolution of the Universe after the Big Bang, providing a world dominated by matter, rather than one where matter and antimatter play comparable roles. To fully explore CP violation in the laboratory needs a dedicated machine - a particle 'factory' - to mass produce B mesons. Only when this full picture of CP violation has been revealed will physicists finally be able to solve its mysteries. As well as major proposals in the US and Japan, several ideas have been launched in Europe. Over the years, many working groups have accumulated an impressive amount of data and knowledge on the physics as well as on the machine and detectors. The spearheads of experimental B physics are the ARGUS and CLEO collaborations. Highlights include the determination of the parameters of the (Cabibbo-Kobayashi-Maskawa, CKM) quark mixing matrix, testing the consistency of the Standard Model with six quarks and three leptons, and giving the first indirect hint that the as yet unseen sixth ('top') quark is very heavy, together with initial indications of how it should decay. Valuable complementary information has come from proton-antiproton collider data and particularly from the LEP experiments at the
Photoproduction and Decay of Light Mesons in CLAS
Amaryan, Moskov Jamalovich [Old Dominion University
2013-08-01
We present preliminary experimental results on photoproduction and decay of light mesons measured with CLAS setup at JLAB . This include Dalitz decay of pseudoscalar and vector mesons, radiative decay of pseudoscalar mesons as well hadronic decays of pseudoscalar and vector mesons. The collected high statistics in some of decay channels exceeds the world data by an order of magnitude and some other decay modes are observed for the first time. It is shown how the CLAS data will improve the world data on transition form factors of light mesons, Dalitz plot analyses, branching ratios of rare decay modes and other fundamental properties potentially accessible through the light meson decays.
Schiraldi, Vito; Morello, Michael Joseph
In fisica delle particelle, con il termine di "oscillazione" si indica la trasformazione di una particella neutra nella sua antiparticella e viceversa, fenomeno dovuto al fatto che gli autostati di flavor non sono autostati della matrice di massa. Il Modello Standard delle interazioni fondamentali predice che l'oscillazione del mesone D^0 avvenga su tempi molto maggiori di una vita media, e appaia perciò come un effetto piccolo, inferiore al percento, in contrasto con il caso dei mesoni B^0 e B^0_s che oscillano con molta maggiore rapidità. Sperimentalmente, l'oscillazione dei mesoni D^0 è rimasta inosservata fino a tempi recenti: la prima evidenza sperimentale dell'esistenza di un effetto di oscillazione è stata ottenuta soltanto nella primavera del 2007 dagli esperimenti BaBar (SLAC, USA) e Belle (KEKB, Japan). Nell'agosto 2007 anche l’esperimento CDF (Fermilab, USA) ha presentato una evidenza simile, basata sull'analisi di una parte del campione di dati disponibile. La tesi descrive gli aspetti speri...
Quarkonium Contribution to Meson Molecules
Cincioglu, E; Ozpineci, A; Yilmazer, A U
2016-01-01
Starting from a molecular picture for the X(3872) resonance, this state and its J^{PC}=2++ HQSS partner [X2(4012)] are analyzed within a model which incorporates possible mixings with 2P charmonium states. Since it is reasonable to expect the bare chi_{c1}(2P) to be located above the D\\bar D* threshold, but relatively close to it, the presence of the charmonium state provides an effective attraction that will contribute to bind the X(3872), but it will not appear in the 2++ sector. Indeed in this latter sector, the chi_{c2}(2P) should provide an effective small repulsion, because it is placed well below the D*\\bar D* threshold. We show how the 1++ and 2++ bare charmonium poles are modified due to the D(*)\\bar D(*) loop effects, and the first one is moved to the complex plane. The meson loops produce, besides some shifts in the masses of the charmonia, a finite width for the 1++ dressed charmonium state. On the other hand, the X(3872) and X2(4012) start developing some charmonium content, which is estimated by...
Meson spectroscopy in the light quark sector
Understanding the hadron spectrum is one of the fundamental issues in modern particle physics. We know that existing hadron configurations include baryons, made of three quarks, and mesons, made of quark-antiquark pairs. However most of the mass of the hadrons is not due to the mass of these elementary constituents but to their binding force. Studying the hadron spectrum is therefore a tool to understand one of the fundamental forces in nature, the strong force, and Quantum Chromo Dynamics (QCD), the theory that describes it. This investigation can provide an answer to fundamental questions as what is the origin of the mass of hadrons, what is the origin of quark confinement, what are the relevant degrees of freedom to describe these complex systems and how the transition between the elementary constituents, quarks and gluons, and baryons and mesons occurs. In this field a key tool is given by meson spectroscopy. Mesons, being made by a quark and an anti-quark, are the simplest quark bound system and therefore the ideal benchmark to study the interaction between quarks and understand what the role of gluons is. In this investigation, it is fundamental to precisely determine the spectrum and properties of mesons but also to search for possible unconventional states beyond the qq-bar configuration as tetra-quarks (qq q-bar q-bar), hybrids (qq-bar g) and glueballs. These states can be distinguished unambiguously from regular mesons when they have exotic quantum numbers, i.e. combinations of total angular momentum, spin and parity that are not allowed for qq-bar states. These are called exotic quantum numbers and the corresponding states are referred to as exotics. The study of the meson spectrum and the search for exotics is among the goals of several experiments in the world that exploit different reaction processes, as e+e- annihilation, pp-bar annihilation, pion scattering, proton-proton scattering and photo-production, to produce meson states. This intense effort
Bottom-strange mesons in hyperonic matter
Pathak, Divakar
2014-01-01
The in-medium behavior of bottom-strange pseudoscalar mesons in hot, isospin asymmetric and dense hadronic environment is studied using a chiral effective model. The same was recently generalized to the heavy quark sector and employed to study the behavior of open-charm and open-bottom mesons. The heavy quark (anti-quark) is treated as frozen and all medium modifications of these bottom-strange mesons are due to their strange anti-quark (quark) content. We observe a pronounced dependence of their medium mass on baryonic density and strangeness content of the medium. Certain aspects of these in-medium interactions are similar to those observed for the strange-charmed mesons in a preceding investigation, such as the lifting of mass-degeneracy of $B_S^0$ and ${\\bar B}_S^0$ mesons in hyperonic matter, while the same is respected in vacuum as well as in nuclear matter. In general, however, there is a remarkable distinction between the two species, even though the formalism predicts a completely analogous in-medium...
Rare meson decays into very light neutralinos
Dreiner, H K; Koschade, Daniel; Krämer, M; Langenfeld, Ulrich; O'Leary, Ben
2009-01-01
We investigate the bounds on the mass of the lightest neutralino from rare meson decays within the MSSM with and without minimal flavor violation. We present explicit formulae for the two-body decays of mesons into light neutralinos and perform the first complete calculation of the loop-induced decays of kaons to pions and light neutralinos and B mesons to kaons and light neutralinos. We find that the supersymmetric branching ratios are strongly suppressed within the MSSM with minimal flavor violation, and that no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed. The branching ratios for kaon and B meson decays into light neutralinos may, however, be enhanced when one allows for non-minimal flavor violation. We find new constraints on the MSSM parameter space for such scenarios and discuss prospects for future kaon and B meson experiments. Finally, we comment on the search for light neutralinos in monojet signatures at the Tevatron and at the LHC.
Rare meson decays into very light neutralinos
Dreiner, H.K.; Grab, S. [Bonn Univ. (Germany). Bethe Center for Theoretical Physics und Physikalisches Inst.; Koschade, D. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik; London Univ. (United Kingdom). Centre for Reserach in String Theory; Kraemer, M.; O' Leary, B. [RWTH Aachen Univ. (Germany). Inst. fuer Theoretische Physik; Langenfeld, U. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany)
2009-05-15
We investigate the bounds on the mass of the lightest neutralino from rare meson decays within the MSSM with and without minimal flavor violation. We present explicit formulae for the two-body decays of mesons into light neutralinos and perform the first complete calculation of the loop-induced decays of kaons to pions and light neutralinos and B mesons to kaons and light neutralinos. We find that the supersymmetric branching ratios are strongly suppressed within the MSSM with minimal flavor violation, and that no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed. The branching ratios for kaon and B meson decays into light neutralinos may, however, be enhanced when one allows for non-minimal flavor violation. We find new constraints on the MSSM parameter space for such scenarios and discuss prospects for future kaon and B meson experiments. Finally, we comment on the search for light neutralinos in monojet signatures at the Tevatron and at the LHC. (orig.)
Light Vector Mesons in the Nuclear Medium
Wood, M H; Weygand, D P; Djalali, C; Tur, C; Mosel, U; Mühlich, P; Adams, G; Amaryan, M J; Ambrozewicz, P; Anghinolfi, M; Asryan, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Battaglieri, M; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, B L; Biselli, A S; Blaszczyk, L; Bouchigny, S; Boiarinov, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Burkert, V D; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Carnahan, B; Casey, L; Chen, S; Cheng, L; Cole, P L; Collins, P; Coltharp, P; Crabb, D; Crannell, H; Credé, V; Cummings, J P; Dashyan, N; De Vita, R; De Sanctis, E; Degtyarenko, P V; Denizli, H; Dennis, L; Deur, A; Dharmawardane, K V; Dickson, R; Dodge, G E; Doughty, D; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Feldman, G; Feuerbach, R J; Fradi, A; Funsten, H; Garçon, M; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gordon, C I O; Gothe, R W; Griffioen, K A; Guidal, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, H; Hakobyan, R S; Hanretty, C; Hardie, J; Hassall, N; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Johnstone, J R; Joo, K; Jüngst, H G; Kalantarians, N; Kellie, J D; Khandaker, M; Khetarpal, P; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Kossov, M; Krahn, Z; Kramer, L H; Kubarovski, V; Kühn, J; Kuhn, S E; Kuleshov, S V; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Ji, Li; Livingston, K; Lu, H Y; MacCormick, M; Markov, N; Mattione, P; McAleer, S; McKinnon, B; McNabb, J W C; Mecking, B A; Mehrabyan, S; Melone, J J; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Mokeev, V; Moriya, K; Morrow, S A; Moteabbed, M; Müller, J; Munevar, E; Mutchler, G S; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Anefalos Pereira, S; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rosner, G; Rossi, P; Sabati, F; Salamanca, J; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabyan, Yu G; Sharov, D; Shvedunov, N V; Smith, E S; Smith, L C; Sober, D I; Sokhan, D; Stavinsky, A; Stepanyan, S; Stepanyan, S S; Stokes, B E; Stoler, P; Strakovsky, I I; Strauch, S; Taiuti, M; Tedeschi, D J; Tkabladze, A; Tkachenko, S; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Watts, D P; Weinstein, L B; Williams, M; Wolin, E; Yegneswaran, A; Zana, L; Zhang, B; Zhang, J; Zhao, B; Zhao, Z W
2008-01-01
The light vector mesons ($\\rho$, $\\omega$, and $\\phi$) were produced in deuterium, carbon, titanium, and iron targets in a search for possible in-medium modifications to the properties of the $\\rho$ meson at normal nuclear densities and zero temperature. The vector mesons were detected with the CEBAF Large Acceptance Spectrometer (CLAS) via their decays to $e^{+}e^{-}$. The rare leptonic decay was chosen to reduce final-state interactions. A combinatorial background was subtracted from the invariant mass spectra using a well-established event-mixing technique. The $\\rho$ meson mass spectrum was extracted after the $\\omega$ and $\\phi$ signals were removed in a nearly model-independent way. Comparisons were made between the $\\rho$ mass spectra from the heavy targets ($A > 2$) with the mass spectrum extracted from the deuterium target. With respect to the $\\rho$-meson mass, we obtain a small shift compatible with zero. Also, we measure widths consistent with standard nuclear many-body effects such as collisional...
Rare meson decays into very light neutralinos
We investigate the bounds on the mass of the lightest neutralino from rare meson decays within the MSSM with and without minimal flavor violation. We present explicit formulae for the two-body decays of mesons into light neutralinos and perform the first complete calculation of the loop-induced decays of kaons to pions and light neutralinos and B mesons to kaons and light neutralinos. We find that the supersymmetric branching ratios are strongly suppressed within the MSSM with minimal flavor violation, and that no bounds on the neutralino mass can be inferred from experimental data, i.e. a massless neutralino is allowed. The branching ratios for kaon and B meson decays into light neutralinos may, however, be enhanced when one allows for non-minimal flavor violation. We find new constraints on the MSSM parameter space for such scenarios and discuss prospects for future kaon and B meson experiments. Finally, we comment on the search for light neutralinos in monojet signatures at the Tevatron and at the LHC. (orig.)
Static-light meson masses from twisted mass lattice QCD
We compute the static-light meson spectrum using two-flavor Wilson twisted mass lattice QCD. We have considered five different values for the light quark mass corresponding to 300 MeVPSS mesons. (orig.)
Review of meson spectroscopy: quark states and glueballs
A group of three lectures on hadron spectroscopy are presented. Topics covered include: light L = 0 mesons, light L = 1 mesons, antiquark antiquark quark quark exotics, a catalogue of higher quark antiquark excitations, heavy quarkonium, and glueballs
Auxiliary Field Meson Model at Finite Temperature and Density
Kouno, H; Kashiwa, K; Hamada, M; Tokudome, H; Matsuzaki, M; Yahiro, M
2005-01-01
Starting from many quark interactions, we construct a nonlinear sigma-omega model at finite temperature and density. The mesons are introduced as auxiliary fields. Effective quark-meson couplings are strongly related to effective meson masses, since they are derived simultaneously from the original many quark interactions. In this model, even if the effective omega-meson mass decreases due to the partial chiral restoration, the equation of state (EOS) of nuclear matter can become soft.
Exclusive vector meson production at HERMES
Movsisyan Aram
2014-06-01
Full Text Available Exclusive electroproduction of vector mesons has been measured on hydrogen and deuterium targets at HERMES using the 27.6 GeV electron/positron beam of HERA. From this process, more information can be obtained about generalized parton distributions (GPDs, which provide a unified description of the structure of hadrons embedding longitudinal-momentum distributions (ordinary PDFs and transverse-position information (form factors. The study of the azimuthal distribution of the decay products via spin-density matrix elements provide constraints on helicity-amplitudes used to describe exclusive vector-meson production. Recent results from the HERMES experiment on the production of rho, omega and phi mesons will be presented.
Exclusive vector meson production at HERMES
Movsisyan, Aram
2014-06-01
Exclusive electroproduction of vector mesons has been measured on hydrogen and deuterium targets at HERMES using the 27.6 GeV electron/positron beam of HERA. From this process, more information can be obtained about generalized parton distributions (GPDs), which provide a unified description of the structure of hadrons embedding longitudinal-momentum distributions (ordinary PDFs) and transverse-position information (form factors). The study of the azimuthal distribution of the decay products via spin-density matrix elements provide constraints on helicity-amplitudes used to describe exclusive vector-meson production. Recent results from the HERMES experiment on the production of rho, omega and phi mesons will be presented.
Massive mesons in Weyl-Dirac theory
Mirabotalebi, S.; Ahmadi, F.; Salehi, H.
2008-01-01
In order to study the mass generation of the vector fields in the framework of a conformal invariant gravitational model, the Weyl-Dirac theory is considered. The mass of the Weyl’s meson fields plays a principal role in this theory, it connects basically the conformal and gauge symmetries. We estimate this mass by using the large-scale characteristics of the observed universe. To do this we firstly specify a preferred conformal frame as a cosmological frame, then in this frame, we introduce an exact possible solution of the theory. We also study the dynamical effect of the massive vector meson fields on the trajectories of an elementary particle. We show that a local change of the cosmological frame leads to a Hamilton-Jacobi equation describing a particle with an adjustable mass. The dynamical effect of the massive vector meson field presents itself in the form of a correction term for the mass of the particle.
Magnetic properties of ground-state mesons
Simonis, Vytautas
2016-01-01
Starting with the bag model a method for the study of the magnetic properties (magnetic moments, magnetic dipole transition widths) of ground-state mesons is developed. We calculate the M1 transition moments and use them subsequently to estimate the corresponding decay widths. These are compared with experimental data, where available, and with the results obtained in other approaches. Finally, we give the predictions for the static magnetic moments of all ground-state vector mesons including those containing heavy quarks. We have a good agreement with experimental data for the M1 decay rates of light as well as heavy mesons. Therefore, we expect our predictions for the static magnetic properties (usual magnetic moments) to be of sufficiently high quality, too.
Nuclear fission induced by Pi mesons
Pi mesons are an important part of the interactions among strongly-interacting particles, and their reactions with complex nuclei involve reactions with a wide range of interactions and time scales, with the slowest being the familiar fission process. Decades of effort have produced a wide range of fission data with stopped and energetic charged beams, both positive and negative. These results are the result of many uncoordinated studies, but in total can give a very good view of pion-induced fission. This review will compare and combine the measurements, with comparisons to a range of theoretical expectations. It is found that the nature of fission induced by pi mesons is not significantly different from fission induced by other energetic particles, in spite of the special features of the mesonic beam. This specific arena of nuclear science may now be considered complete. (author)
Mesons beyond the naive quark model
Amsler, C
2004-01-01
We discuss theoretical predictions for the existence of exotic (non-quark-model) mesons and review prominent experimental candidates. These are especially the f0(1500) and f0(1710) mesons for the scalar glueball, fJ(2220) for the tensor glueball, η(1410) for the pseudoscalar glueball, f0(600), f0(980), a0(980), the still to be firmly established κ(800) and the f2(1565) for or two-meson states, and π1(1400), π1(1600) for hybrid states. We conclude that some of these states exist, offer our views and discuss crucial issues that need to be investigated both theoretically and experimentally.
Through a special interplay of strong and weak interactions, small but significant pieces with a ''wrong'' flavor could be introduced into wave functions of mesons. Thus, e.g., not only a (u bar s) pair, but also a (u bar d) pair can be found with some probability within K+, etc. The possible importance of such ''anomalous'' terms in understanding of K-meson decays is discussed in a new scheme. The scheme is characterized by diagrammatic calculations of full amplitudes in the long-distance environment. Two classes of models which correctly reproduce the main K-meson branching ratios and the ΔI=1/2 rule are constructed. The predictive power of the scheme is then tested in a decay of a kaon into a pion and a light hyperphoton
Two, three, many body systems involving mesons
Oset, E; Khemchandani, K P; Roca, L; Yamagata, J
2011-01-01
In this talk we show recent developments on few body systems involving mesons. We report on an approach to Faddeev equations using chiral unitary dynamics, where an explicit cancellation of the two body off shell amplitude with three body forces stemming from the same chiral Lagrangians takes place. This removal of the unphysical off shell part of the amplitudes is most welcome and renders the approach unambiguous, showing that only on shell two body amplitudes need to be used. Within this approach, systems of two mesons and one baryon are studied, reproducing properties of the low lying $1/2^+$ states. On the other hand we also report on multirho and $K^*$ multirho states which can be associated to known meson resonances of high spin.
eta' meson production in proton-proton collisions
K Nakayama; Arellano, H. F.; Durso, J.W.; Speth, J.(Institut für Kernphysik, Forschungszentrum Jülich, Jülich, D-52425, Germany)
1999-01-01
The pp -> pp eta' reaction is investigated within a relativistic meson-exchange model of hadronic interactions. We explore the role of nucleonic and mesonic, as well as the N* resonance currents, in producing eta' mesons. In order to learn more about the production mechanisms, new measurements in the energy region far from the threshold are required.
Scalar mesons in a linear sigma model with (axial-)vector mesons
Parganlija, D; Wolf, Gy; Giacosa, F; Rischke, D H
2012-01-01
The structure of the scalar mesons has been a subject of debate for many decades. In this work we look for $\\bar{q}q$ states among the physical resonances using an extended Linear Sigma Model that contains scalar, pseudoscalar, vector, and axial-vector mesons both in the non-strange and strange sectors. We perform global fits of meson masses, decay widths and amplitudes in order to ascertain whether the scalar $\\bar{q}q$ states are below or above 1 GeV. We find the scalar states above 1 GeV to be preferred as $\\bar{q}q$ states.
Scalar mesons from an effective Lagrangian approach
Fariborz, Amir H; Schechter, Joseph
2007-01-01
A brief discussion of the recent interest in light scalar mesons motivates the study of a generalized linear sigma model. In an SU(3) flavor invariant version of the model there is a prediction that the the lighter scalars have sizeable "four quark" content. It is further predicted that one of the singlet scalars should be exceptionally light. Due to the presence of scalar mesons, the model gives "controlled" corrections to the current algebra formula for threshold pion pion scattering. These corections act in the direction to improve agreement with current experiments.
Light $O^{++}$ Mesons: Scalargators in Florida
Pennington, M R
2010-01-01
Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment at JLab, making an understanding (or at least an excellent and theoretically consistent description) essential for the physics missions of these facilities.
Heavy Meson Molecules in Effective Field Theory
AlFiky, Mohammad T.; Gabbiani, Fabrizio; Petrov, Alexey A.
2006-01-01
We consider the implications from the possibility that the recently observed state X(3872) is a meson-antimeson molecule. We write an effective Lagrangian consistent with the heavy-quark and chiral symmetries needed to describe X(3872). We explore the consequences of the assumption that X(3872) is a molecular bound state of D^{*0} and anti-D^0 mesons for the existence of bound states in the D^0-anti-D^0 and D^{*0}-anti-D^{*0}.
Turbulent meson condensation in quark deconfinement
Koji Hashimoto
2015-06-01
Full Text Available In a QCD-like strongly coupled gauge theory at large Nc, using the AdS/CFT correspondence, we find that heavy quark deconfinement is accompanied by a coherent condensation of higher meson resonances. This is revealed in non-equilibrium deconfinement transitions triggered by static, as well as quenched electric fields even below the Schwinger limit. There, we observe a “turbulent” energy flow to higher meson modes, which finally results in the quark deconfinement. Our observation is consistent with seeing deconfinement as a condensation of long QCD strings.
Mass shift of -meson in nuclear matter
J R Morones-Ibarra; Mónica Menchaca Maciel; Ayax Santos-Guevara; Felipe Robledo Padilla
2013-03-01
The propagation of -meson in nuclear matter is studied in the Walecka model, by assuming that the sigma couples to a pair of nucleon–antinucleon states and to particle–hole states. The in-medium effect of - mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the -meson mass decreases with respect to its value in vacuum and that the contribution of the - mixing effect on the mass shift is relatively small.
Diffractive hadroproduction of charmed D mesons
We have observed charmed D meson production from a hydrogen target in a 217 GeV/c π- beam. Hadronic decays in the K+-π+-π+- channels were reconstructed in the Chicago Cyclotron Spectrometer at Fermilab. The proton recoil angle and momentum transfer were programmed so that objects of mass near that of two D mesons would be produced in the forward direction. A mass peak in the 40-MeV bin at 1875 MeV was found in each channel. The cross section for D+- production is 6--10 μb
Isospin-violating mixing in meson nonets
Segregation into ideally mixed nonets results when the OZI-violating interaction which would mix u anti u, d anti d, and s anti s mesons into isospin and SU(3) eigenstates is much weaker than the s anti s-d anti d mass difference. We show that the d anti d-u anti u mass difference can begin to induce a similar segregation into d anti d and anti u mesons which leads to large isospin violations. An experimental example of such large isospin breaking (approx. 30%) which we predict has probably already been seen in f → K anti K. (orig.)
CP violation in B meson decays
Noguchi, S.; Belle Group
2003-06-01
CP violation in neutral B meson decays has been observed confirming the prediction of the Kobayashi-Maskawa model where introduction of six quaks naturally induces CP violation in the weak interaction. The measurements of CP asymmetryc in B meson decays were made at the newly constructed Asymmetric B factories, which consist of high luminosity, ebergy-asymmetric e+e- colliders (KEKB and PEP-II) and detectors (Belle and BaBar). The results are in good agreement and are consistent with other experimental results within the framework of the Standard Model.
Soft-wall modelling of meson spectra
Afonin, S S
2016-01-01
The holographic methods inspired by the gauge/gravity correspondence from string theory have been actively applied to the hadron spectroscopy in the last eleven years. Within the phenomenological bottom-up approach, the linear Regge-like trajectories for light mesons are naturally reproduced in the so-called "Soft-wall" holographic models. I will give a very short review of the underlying ideas and technical aspects related to the meson spectroscopy. A generalization of soft-wall description of Regge trajectories to arbitrary intercept is proposed. The problem of incorporation of the chiral symmetry breaking is discussed.
$B$ and $B_s$ Meson Spectroscopy
Godfrey, S; Swanson, E S
2016-01-01
Properties of bottom and bottom-strange mesons are computed in two relativized quark models. Model masses and wavefunctions are used to predict radiative transition rates and the $^3P_0$ quark pair creation model is used to compute strong decay widths. A comparison to recently observed bottom and bottom-strange states is made. We find that there are numerous excited $B$ and $B_s$ mesons that have relatively narrow widths and significant branching ratios to simple final states such as $B\\pi$, $B^*\\pi$, $BK$, and $B^*K$ that could be observed in the near future.
Light O++ Mesons: Scalargators in Florida
Light scalar mesons abound in hadron processes, like the alligators in the Florida Everglades. Moreover, scalars are intimately tied to the vacuum structure of QCD. They are the product of many decays. Consequently, a rich source of recent information about them has come from experiments producing heavy flavour mesons. Indeed, scalars will continue to dominate many of the processes to be studied at forthcoming facilities like BESIII in Beijing, FAIR at GSI Darmstadt and the GlueX experiment at JLab, making an understanding (or at least an excellent and theoretically consistent description) essential for the physics missions of these facilities.
Quasi-exotic open-flavor mesons
Hilger, T
2016-01-01
Meson states with exotic quantum numbers arise naturally in a covariant bound-state framework in QCD. We investigate the consequences of shifting quark masses such that the states are no longer restricted to certain C-parities, but only by J^P. Then, a priori, one can no longer distinguish exotic or conventional states. In order to identify signatures of the different states to look for experimentally, we provide the behavior of masses, leptonic decay constants, and orbital-angular-momentum decomposition of such mesons, as well as the constellations in which they could be found. Most prominently, we consider the case of charged quasi-exotic excitations of the pion.
Pseudoscalar meson physics with four dynamical quarks
Bazavov, A; Bouchard, C; DeTar, C; Du, D; El-Khadra, A X; Foley, J; Freeland, E D; Gamiz, E; Gottlieb, Steven; Heller, U M; Hetrick, J E; Kim, J; Kronfeld, A S; Laiho, J; Levkova, L; Lightman, M; Mackenzie, P B; Neil, E T; Oktay, M; Simone, J N; Sugar, R L; Toussaint, D; Van de Water, R S; Zhou, R
2012-01-01
We present preliminary results for light, strange and charmed pseudoscalar meson physics from simulations using four flavors of dynamical quarks with the highly improved staggered quark (HISQ) action. These simulations include lattice spacings ranging from 0.15 to 0.06 fm, and sea-quark masses both above and at their physical value. The major results are charm meson decay constants f_D, f_{D_s} and f_{D_s}/f_D and ratios of quark masses. This talk will focus on our procedures for finding the decay constants on each ensemble, the continuum extrapolation, and estimates of systematic error.
Issues in light meson spectroscopy: The case for meson spectroscopy at CEBAF
Godfrey, S. [Carleton Univ., Ottawa (Canada)
1994-04-01
The author reviews some outstanding issues in meson spectroscopy. The most important qualitative issue is whether hadrons with explicit gluonic degrees of freedom exist. To answer this question requires a much better understanding of conventional q{bar q} mesons. The author therefore begins by examining the status of conventional meson spectroscopy and how the situation can be improved. The expected properties of gluonic excitations are discussed with particular emphasis on hybrids to give guidance to experimental searches. Multiquark systems are commented upon as they are likely to be important in the mass region under study and will have to be understood better. In the final section the author discusses the opportunities that CEBAF can offer for the study of meson spectroscopy.
Effects of isovector scalar meson on hyperon star
Biswal, S K; Patra, S K
2016-01-01
We study the effects of isovector-scalar ($\\delta$)-meson on neutron star. Influence of $\\delta$-meson on both static and rotating neutron star is discussed. Inclusion of $\\delta$-meson in a neutron star system consisting of proton, neutron and electron, make the equation of state stiffer in higher density and consequently increases the maximum mass of the star. But induction of $\\delta$-meson in the hyperon star decreases the maximum mass of the hyperon star. This is due to the early evolution of hyperons in presence of $\\delta-$meson.
Three body resonances in two meson-one baryon systems
Martínez Torres, Alberto; Khemchandani, K. P.; Oset Báguena, Eulogio
2007-01-01
We report four $\\Sigma$'s and three $\\Lambda$'s, in the 1500 - 1800 MeV region, as two meson - one baryon S-wave $(1/2)^+$ resonances. We solve Faddeev equations in the coupled channel approach. The invariant mass of one of the meson-baryon pairs and that of the three particles have been varied and peaks in the squared three body $T$-matrix have been found very close to the existing $S$ = -1, $J^P= 1/2^+$ low lying baryon resonances. The input two-body $t$-matrices for meson-meson and meson-b...
Two, three, many body systems involving mesons. Multimeson condensates
Oset, E; Dote, A; Hyodo, T; Khemchandani, P K; Liang, W H; Torres, A Martinez; Oka, M; Roca, L; Uchino, T; Xiao, C W
2015-01-01
In this talk we review results from studies with unconventional many hadron systems containing mesons: systems with two mesons and one baryon, three mesons, some novel systems with two baryons and one meson, and finally systems with many vector mesons, up to six, with their spins aligned forming states of increasing spin. We show that in many cases one has experimental counterparts for the states found, while in some other cases they remain as predictions, which we suggest to be searched in BESIII, Belle, LHCb, FAIR and other facilities.
Nuclear matter with constituent meson quanta
The authors discuss some nonperturbative techniques of field theory, where they dress nuclear matter as a whole with off-mass-shell pions. Here s-wave pion pairs simulate the effect of σ-meson of the mean field approach of Walecka. The signatures are in agreement with earlier results along with new physical insight
New physics effects from meson decays
Anirban Kundu
2000-07-01
In this talk, we point out some of the present and future possible signatures of physics beyond the Standard Model from -meson decays, taking -parity conserving and violating supersymmetry as illustrative examples. An expanded version is available on hep-ph archive.
QED effects in the pseudoscalar meson sector
Horsley, R.; Nakamura, Y.; Perlt, H.; Pleiter, D.; Rakow, P. E. L.; Schierholz, G.; Schiller, A.; Stokes, R.; Stüben, H.; Young, R. D.; Zanotti, J. M.
2016-04-01
In this paper we present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED, concentrating particularly on violations of isospin symmetry. We calculate the π +- π 0 splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in [1]. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the u and d quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen's theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as overline{M S} , in which Dashen's theorem for neutral mesons is violated.
Meson Screening Masses in Thermal QCD
Czerski Piotr
2012-12-01
Full Text Available The quark-gluon plasma (QGP excitations, corresponding to the scalar and pseudoscalar meson quantum numbers, for different temperatures are calculated. Analysis is performed in the Hard Thermal Loop (HTL Approximation and leads to a better understanding of the excitations of QGP in the deconfined phase and is also of relevance for lattice studies.
Charming Mesons with Baryons and Nuclei
Tolos, Laura
2013-11-01
The properties of charmed mesons in nuclear matter and nuclei are reviewed. Different frameworks are discussed paying a special attention to unitarized coupled-channel approaches which incorporate heavy-quark spin symmetry. Several charmed baryon states with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. These states are compared to experimental data. Moreover, the properties of open-charm mesons in matter are analyzed. The in-medium solution accounts for Pauli blocking effects, and for the meson self-energies in a self-consistent manner. The behavior in the nuclear medium of the rich spectrum of dynamically-generated baryon states is studied as well as their influence in the self-energy and, hence, the spectral function of open charm. The possible experimental signatures of the in-medium properties of open charm are finally addressed, such as the formation of charmed nuclei, in connection with the future FAIR facility.
Charming mesons with baryons and nuclei
Tolos, Laura
2013-01-01
The properties of charmed mesons in nuclear matter and nuclei are reviewed. Different frameworks are discussed paying a special attention to unitarized coupled-channel approaches which incorporate heavy-quark spin symmetry. Several charmed baryon states with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with $1/2^+$ and $3/2^+$ baryons. These states are compared to experimental data. Moreover, the properties of open-charm mesons in matter are analyzed. The in-medium solution accounts for Pauli blocking effects, and for the meson self-energies in a self-consistent manner. The behavior in the nuclear medium of the rich spectrum of dynamically-generated baryon states is studied as well as their influence in the self-energy and, hence, the spectral function of open charm. The possible experimental signatures of the in-medium properties of open charm are finally addressed, such as the formation of charmed nuclei, in connection with the future F...
Chiral dynamics of heavy-light mesons
This thesis focuses on the physics of heavy-light mesons, i.e. quark-antiquark systems composed of a heavy (c or b) and a light (u, d or s) quark. The light-quark sector is treated within the framework of chiral effective field theory. Recent lattice QCD computations have progressed in determining the decay constants of charmed mesons and the scattering lengths of Nambu-Goldstone bosons (pions, kaons) off D mesons. These computations are performed for light quark masses larger than the physical ones. A chiral extrapolation down to physical masses is necessary. It is commonly performed using chiral perturbation theory. The related systematical uncertainties have to be examined carefully. In this thesis it is shown how these uncertainties can be reduced significantly by taking into account relativistic effects in the chiral extrapolations. As a byproduct, estimates are presented for several physical quantities that are related by heavy-quark spin and flavor symmetry. Furthermore, the investigation of the light-quark mass dependence of the scattering lengths of Nambu-Goldstone bosons off D mesons provides important information on the nature of one of the intriguing newly discovered resonances, the D*s0(2317). It is shown that this resonance can be dynamically generated from the coupled-channels DK interaction without a priori assumption of its existence. Finally we demonstrate how the underlying framework, unitarized chiral perturbation theory, can be improved by the inclusion of intermediate states with off-the-mass-shell kinematics.
Hermaphrodite mesons and QCD sum rules
We present a new evaluation of the two-point function built from the colourless operators g anti psilambdasup(α)γν(γ5)psiFsup(μν)sub(α). Previous calculations for the dimension-six vacuum condensate contributions were incomplete. We give new predictions for the masses and decay amplitudes of 1-+ and 0-- hermaphrodite mesons. (orig.)
QED effects in the pseudoscalar meson sector
We present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED. We concentrate particularly on violations of isospin symmetry. We calculate the π+-π0 splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in arXiv:1508.06401 [hep-lat]. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the u and d quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen's theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as MS, in which Dashen's theorem for neutral mesons is violated.
On the Origin of the $XYZ$ Mesons
Valcarce, A
2016-01-01
In this talk we present a mechanism giving rise to exotic $XYZ$ four-quark states in the meson spectra within a constituent quark model approach. We discuss its generalization to five-quark states in the heavy baryon sector. Finally, we revise some other works in the literature and experimental data where this mechanism may be working.
Composite vector mesons and string models
The author discusses the general question of gauge mesons in extended supergravities, and whether such theories can produce the gauge mesons corresponding to a group at least as large as SU(3) x SU(2) x U(1). An exciting conjecture in this direction was made a few years ago by previous authors, who suggested that there might be composite SU(8) gauge mesons in a supergravity model known as the N=8 model. Until we have a consistent, renormalizable theory of supergravity we cannot really obtain any indication of the truth or falseness of that conjecture. One form of the Neveu-Schwarz string model has been shown to be a theory of supergravity; it is finite at the one-loop level and probably in any order of perturbation theory. The discussion is within the framework of this model. The author questions whether massive vector mesons can possibly lose their mass due to interactions. Arguments have been given on both sides of this question, and the author believes that this can occur under certain circumstances. Our conclusions is that the FNNS mechanism will create a gauge symmetry in addition to the rigid symmetry
Mesons in the Constituent Quark Model
WANG Li; PING Jia-Lun
2007-01-01
The quark-antiquark (q(-q)) spectrum is studied by solving the Schrǒdinger equation in the framework of non-relativistic constituent quark model. An overall good fit to the experimental data of meson is obtained. The interactions between quark and antiquark consist of quadratic colour confinement-exchange, one-gluon-exchange, and Goldstone-boson-exchange potentials.
Probing Polarized Parton Distributions with Meson Photoproduction
Afanasiev, A M; Wahlquist, C; Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian
1997-01-01
Polarization asymmetries in photoproduction of high transverse momentum mesons are a flavor sensitive way to measure the polarized quark distributions. We calculate the expected asymmetries in several models, and find that the asymmetries are significant and also significantly different from model to model. Suitable data may come as a by-product of deep inelastic experiments to measure $g_1$ or from dedicated experiments.
Mesonic spectroscopy of Minimal Walking Technicolor
Del Debbio, Luigi; Lucini, Biagio; Patella, Agostino; Pica, Claudio; Rago, Antonio
2010-01-01
We investigate the structure and the novel emerging features of the mesonic non-singlet spectrum of the Minimal Walking Technicolor (MWT) theory. Precision measurements in the nonsinglet pseudoscalar and vector channels are compared to the expectations for an IR-conformal field theory and a QCD...
L = 1 light quark mesons in QCD
Using the Borel transformed QCD sum rule formalism, the masses of L = 1 light quark mesons with isospin I = 1 and I = 0 are calculated. Non-perturbative effects from higher dimensional operators up to dimension d = 6 in the operator product expansion are taken into account. (orig.)
Meson spectroscopy in large-N QCD
Castagnini, Luca
2015-06-23
We present the results of a systematic, first-principles study of the spectrum and decay constants of mesons for different numbers of color charges N, via lattice computations. We discuss the extrapolations to the chiral, continuum and large-N limits and present a comparison of our results to some of the numerical computations and analytical predictions available in the literature.
Lattice investigation of heavy meson interactions
Wagenbach, Björn; Bicudo, Pedro; Wagner, Marc
2014-01-01
We report on a lattice investigation of heavy meson interactions and of tetraquark candidates with two very heavy quarks. These two quarks are treated in the static limit, while the other two are up, down, strange or charm quarks of finite mass. Various isospin, spin and parity quantum numbers are considered.
Bc mesons in the deconfined phase
Czerski Piotr
2014-01-01
Full Text Available Charmed B mesons in a deconfined quark-gluon plasma are studied. With the introduction of the bound state of a charm and a beauty quarks at finite temperature, the behavior of the heavy quarkonium is investigated in an energy region between the ψ and the ϒ states [1]. Calculations are performed within a potential model [2, 3].
Scattering of vector mesons off nucleons
We construct a relativistic and unitary approach to 'high' energy pion- and photon-nucleon reactions taking the πN, πΔ, ρN, ωN, ηN, K Λ, KΣ final states into account. Our scheme dynamically generates the s- and d-wave nucleon resonances N(1535), N(1650) and N(1520) and isobar resonances Δ(1620) and δ(1700) in terms of quasi-local interaction vertices. The description of photon-induced processes is based on a generalized vector-meson dominance assumption which directly relates the electromagnetic quasi-local 4-point interaction vertices to the corresponding vertices involving the ρ and ω fields. We obtain a satisfactory description of the elastic and inelastic pion- and photon-nucleon scattering data in the channels considered. The resulting s-wave ρ- and ω-nucleon scattering amplitudes are presented. Using these amplitudes we compute the leading density modification of the ρ and ω mass distributions in nuclear matter. We find a repulsive mass shift for the ω meson at small nuclear density but predict considerable strength in resonance-hole like ω-meson modes. Compared to previous calculations our result for the ρ-meson spectral function shows a significantly smaller in-medium effect. This reflects a not too large coupling strength of the N(1520) resonance to the ρN channel. (orig.)
Meson spectroscopy in large-N QCD
We present the results of a systematic, first-principles study of the spectrum and decay constants of mesons for different numbers of color charges N, via lattice computations. We discuss the extrapolations to the chiral, continuum and large-N limits and present a comparison of our results to some of the numerical computations and analytical predictions available in the literature.
Summary of the {eta}-meson sessions
Chrien, R.E.
1993-06-01
This summary describes the contents of the nineteen talks related to research on the {eta} meson and presented at the Workshop of Future Directions. The subjects of this area include threshold {eta} production, {eta}-nuclear spectroscopy, baryon spectroscopy, {eta} decays, facilities, and instrumentation.
Summary of the [eta]-meson sessions
Chrien, R.E.
1993-01-01
This summary describes the contents of the nineteen talks related to research on the [eta] meson and presented at the Workshop of Future Directions. The subjects of this area include threshold [eta] production, [eta]-nuclear spectroscopy, baryon spectroscopy, [eta] decays, facilities, and instrumentation.
Finite-size scaling of meson propagators
Using quenched chiral perturbation theory we compute meson correlation functions at finite volume and fixed gauge field topology. We also present the corresponding analytical predictions for the unquenched theory at fixed gauge field topology. These results can be used to measure the low-energy parameters of the chiral Langrangian from lattice simulations in volumes much smaller than one pion Compton wavelength. (orig.)
QED effects in the pseudoscalar meson sector
Horsley, R. [Edinburgh Univ. (United Kingdom). School of Physics and Astronomy; Nakamura, Y. [RIKEN Advanced Institute for Computational Science, Kobe (Japan); Perlt, H. [Leipzig Univ. (Germany). Inst. fuer Theoretische Physik; Collaboration: QCDSF-UKQCD Collaboration; and others
2015-09-15
We present results on the pseudoscalar meson masses from a fully dynamical simulation of QCD+QED. We concentrate particularly on violations of isospin symmetry. We calculate the π{sup +}-π{sup 0} splitting and also look at other isospin violating mass differences. We have presented results for these isospin splittings in arXiv:1508.06401 [hep-lat]. In this paper we give more details of the techniques employed, discussing in particular the question of how much of the symmetry violation is due to QCD, arising from the different masses of the u and d quarks, and how much is due to QED, arising from the different charges of the quarks. This decomposition is not unique, it depends on the renormalisation scheme and scale. We suggest a renormalisation scheme in which Dashen's theorem for neutral mesons holds, so that the electromagnetic self-energies of the neutral mesons are zero, and discuss how the self-energies change when we transform to a scheme such as MS, in which Dashen's theorem for neutral mesons is violated.
On hadronic production of the Bc meson
Various approaches to the hadronic productions of the double heavy meson Bc are investigated in this paper. The resultant cross sections obtained by the approaches are compared with in several aspects. One may see that the differences are quite substantial. The advantages and shortcomings of the approaches are discussed. (author). 17 refs, 4 figs
Meson Spectroscopy at JLab-12 GeV
Meson, being the simplest hadronic bound system, is the ideal 'laboratory' to study the interaction between quarks, to understand the role of the gluons inside hadrons and to investigate the origin of color confinement. To perform such studies it is important to measure the meson spectrum, with precise determination of resonance masses and properties, looking for rare q q-bar states and for unconventional mesons with exotic quantum numbers (i.e. mesons with quantum numbers that are not compatible with a q q-bar structure). With the imminent advent of the 12 GeV upgrade of Jefferson Lab a new generation of meson spectroscopy experiments will start: 'Meson-Ex' in Hall B and 'GLUEX' in Hall D. Both will use photo-production to explore the spectrum of mesons in the light-quark sector, in the energy range of few GeVs.
Meson Spectroscopy at JLab@12 GeV
Celentano, Andrea [INFN-GENOVA
2013-03-01
Meson, being the simplest hadronic bound system, is the ideal "laboratory" to study the interaction between quarks, to understand the role of the gluons inside hadrons and to investigate the origin of color confinement. To perform such studies it is important to measure the meson spectrum, with precise determination of resonance masses and properties, looking for rare qbar q states and for unconventional mesons with exotic quantum numbers (i.e. mesons with quantum numbers that are not compatible with a qbar q structure). With the imminent advent of the 12 GeV upgrade of Jefferson Lab a new generation of meson spectroscopy experiments will start: "Meson-Ex" in Hall B and "GLUEX" in Hall D. Both will use photo-production to explore the spectrum of mesons in the light-quark sector, in the energy range of few GeVs.
Studies on inclusive meson resonance and particle production
Production and decay of meson resonances are studied in medium energy meson-proton collisions. Strong evidence is found that hadronic collisions are dominated by resonance production. Especially the vector mesons have often large inclusive cross sections, typically of the order of few millibarns at the present energies. In all, a majority of pions and kaons appear to be decay products of resonances or other unstable particles. The detailed kinematics of the parent resonance's decays is found to play an important role in determining inclusive pion spectra. The squared transverse momentum distributions of hadrons heavier than the pion appear to have in common an exponential behaviour, with a universal slope for the esponential fall-off. The observed vector meson yields suggest that only a small fraction of the direct lepton production observed at large transverse momentum in nucleon-nucleon interactions is accounted for by the ''old'' vector mesons. An attempt has been made to separate out the central production and fragmentation components of the meson production. Both the central production and the fragmentation of the incoming meson are found to be important mechanisms in the non-strange meson production whereas the central production of strange meson resonances is rare at our energies. The ratios of the observed meson yields are found to be generally in good agreement with a simple quark-counting model. (author)
Spin O decay angular distribution for interfering mesons in electroproduction
Funsten, H.; Gilfoyle, G.
1994-04-01
Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W({theta},{psi}). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W({theta},{psi}) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter`s relative orbital angular momentum m-projection; none is {open_quotes}absorbed{close_quotes} into daughter helicities. The decaying meson`s helicity maximally appears in W({theta},{psi}). W({theta},{psi}) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W({theta},{psi}) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W ({theta},{psi}), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters.
Heavy meson spectroscopy under strong magnetic field
Yoshida, Tetsuya
2016-01-01
Spectra of the neutral heavy mesons, $\\eta_c(1S,2S)$, $J/psi$, $\\psi(2S)$, $\\eta_b(1S,2S,3S)$, $\\Upsilon(1S,2S,3S)$, $D$, $D^\\ast$, $B$, $B^\\ast$, $B_s$ and $B_s^\\ast$, in a homogeneous magnetic field are analyzed in a potential model of constituent quarks. To obtain anisotropic wave functions and the corresponding eigenvalues, the cylindrical Gaussian expansion method is applied, where the wave functions for transverse and longitudinal directions in the cylindrical coordinate are expanded by the Gaussian bases separately. Energy level structures in the wide range of magnetic field are obtained and the deformation of the wave functions is shown, which reflects effects of the spin mixing, the Zeeman splitting and quark Landau levels. The contribution from the magnetic catalysis in heavy-light mesons is discussed as a change of the light constituent quark mass.
Neutral-meson oscillations with torsion
Poplawski, Nikodem J
2011-01-01
We propose a simple mechanism that may explain the observed particle-antiparticle asymmetry in the Universe. In the Einstein-Cartan-Sciama-Kibble theory of gravity, the intrinsic spin of matter generates spacetime torsion. Classical Dirac fields in the presence of torsion obey the nonlinear Hehl-Datta equation which is asymmetric under a charge-conjugation transformation. Accordingly, at extremely high densities that existed in the very early Universe, fermions have higher effective masses than antifermions. As a result, a meson composed of a light quark and a heavy antiquark has a lower effective mass than its antiparticle. Neutral-meson oscillations in thermal equilibrium therefore favor the production of light quarks and heavy antiquarks, which may be related to baryogenesis.
The lightest hybrid meson supermultiplet in QCD
Dudek, Jozef J
2011-10-01
We interpret the spectrum of meson states recently obtained in non-perturbative lattice QCD calculations in terms of constituent quark-antiquark bound states and states, called 'hybrids', in which the q{bar q} pair is supplemented by an excitation of the gluonic field. We identify a lightest supermultiplet of hybrid mesons with J{sup PC} = (0,1,2){sup {-+}}, 1{sup -} built from a gluonic excitation of chromomagnetic character coupled to q{bar q} in an S-wave. The next lightest hybrids are suggested to be quark orbital excitations with the same gluonic excitation, while the next distinct gluonic excitation is significantly heavier. Existing models of gluonic excitations are compared to these findings and possible phenomenological consequences explored.
Exclusive electroproduction of $\\phi$ mesons at HERA
Chekanov, S; Adamczyk, L; Adamus, M; Adler, V; Aghuzumtsyan, G; Allfrey, P D; Antonioli, P; Antonov, A; Arneodo, M; Bailey, D S; Bamberger, A; Barakbaev, A N; Barbagli, G; Barbi, M; Bari, G; Barreiro, F; Bartsch, D; Basile, M; Behrens, U; Bell, M A; Bellagamba, L; Bellan, P M; Benen, A; Bertolin, A; Bhadra, S; Bloch, I; Bold, T; Boos, E G; Borras, K; Boscherini, D; Brock, I; Brook, N H; Brugnera, R; Brümmer, N; Bruni, A; Bruni, G; Bussey, P J; Butterworth, J M; Büttner, C; Bylsma, B; Caldwell, A; Capua, M; Cara Romeo, G; Carli, T; Carlin, R; Cassel, D G; Catterall, C D; Abramowicz, H; Chwastowski, J; Ciborowski, J; Ciesielski, R; Cifarelli, Luisa; Cindolo, F; Cole, J E; Collins-Tooth, C; Contin, A; Cooper-Sarkar, A M; Coppola, N; Corradi, M; Corriveau, F; Costa, M; Cottrell, A; Cui, Y; D'Agostini, G; Dal Corso, F; Danilov, P; De Pasquale, S; Dementiev, R K; Derrick, M; Devenish, R C E; Dhawan, S; Dobur, D; Dolgoshein, B A; Doyle, A T; Drews, G; Durkin, L S; Dusini, S; Eisenberg, Y; Ermolov, P F; Eskreys, Andrzej; Everett, A; Ferrando, J; Ferrero, M I; Figiel, J; Foster, B; Foudas, C; Fourletov, S; Fourletova, J; Fry, C; Gabareen, A; Galas, A; Gallo, E; Garfagnini, A; Geiser, A; Genta, C; Gialas, I; Giusti, P; Gladilin, L K; Gladkov, D; Glasman, C; Göbel, F; Goers, S; Goncalo, R; González, O; Gosau, T; Göttlicher, P; Grabowska-Bold, I; Graciani-Díaz, R; Grigorescu, G; Grijpink, S; Groys, M; Grzelak, G; Gutsche, O; Gwenlan, C; Haas, T; Hain, W; Hall-Wilton, R; Hamatsu, R; Hamilton, J; Hanlon, S; Hart, C; Hartmann, H; Hartner, G; Heaphy, E A; Heath, G P; Helbich, M; Hilger, E; Hochman, D; Holm, U; Horn, C; Iacobucci, G; Iga, Y; Irrgang, P; Jakob, H P; Jiménez, M; Jones, T W; Kagawa, S; Kahle, B; Kaji, H; Kananov, S; Karshon, U; Karstens, F; Kasemann, M; Kataoka, M; Katkov, I I; Kcira, D; Keramidas, A; Khein, L A; Kim, J Y; Kind, O; Kisielewska, D; Kitamura, S; Koffeman, E; Kohno, T; Kooijman, P; Koop, T; Korzhavina, I A; Kotanski, A; Kötz, U; Kowal, A M; Kowalski, H; Kramberger, G; Kreisel, A; Krumnack, N; Kulinski, P; Kuze, M; Kuzmin, V A; Labarga, L; Lammers, S; Lelas, D; Levchenko, B B; Levy, A; Li, L; Lightwood, M S; Lim, H; Limentani, S; Ling, T Y; Liu, C; Liu, X; Löhr, B; Lohrmann, E; Loizides, J H; Long, K R; Longhin, A; Lukasik, J; Lukina, O Yu; Luzniak, P; Ma, K J; Maddox, E; Magill, S; Malka, J; Mankel, R; Margotti, A; Marini, G; Martin, J F; Martínez, M; Mastroberardino, A; Matsuzawa, K; Mattingly, M C K; Melzer-Pellmann, I A; Menary, S R; Metlica, F; Meyer, U; Miglioranzi, S; Milite, M; Mirea, A; Monaco, V; Montanari, A; Musgrave, B; Nagano, K; Namsoo, T; Nania, R; Nguyen, C N; Nigro, A; Ning, Y; Noor, U; Notz, D; Nowak, R J; Nuncio-Quiroz, A E; Oh, B Y; Olkiewicz, K; Ota, O; Padhi, S; Palmonari, F; Patel, S; Paul, E; Pavel, Usan; Pawlak, J M; Pelfer, P G; Pellegrino, A; Pesci, A; Piotrzkowski, K; Plamondon, M; Plucinsky, P P; Pokrovskiy, N S; Polini, A; Proskuryakov, A S; Przybycien, M B; Rautenberg, J; Raval, A; Reeder, D D; Ren, Z; Renner, R; Repond, J; Ri, Y D; Rinaldi, L; Robins, S; Rosin, M; Ruspa, M; Ryan, P; Sacchi, R; Salehi, H; Santamarta, R; Sartorelli, G; Savin, A A; Saxon, D H; Schagen, S; Schioppa, M; Schlenstedt, S; Schleper, P; Schmidke, W B; Schneekloth, U; Schörner-Sadenius, T; Sciulli, F; Shcheglova, L M; Skillicorn, I O; Slominski, W; Smith, W H; Soares, M; Solano, A; Son, D; Sosnovtsev, V V; Stairs, D G; Stanco, L; Standage, J; Stifutkin, A; Stonjek, S; Stopa, P; Stösslein, U; Straub, P B; Suchkov, S; Susinno, G; Suszycki, L; Sutiak, J; Sutton, M R; Sztuk, J; Szuba, D; Szuba, J; Tapper, A D; Targett-Adams, C; Tassi, E; Tawara, T; Terron, J; Tiecke, H G; Tokushuku, K; Tsurugai, T; Turcato, M; Tymieniecka, T; Tyszkiewicz, A; Ukleja, A; Ukleja, J; Vázquez, M; Vlasov, N N; Voss, K C; Walczak, R; Walsh, R; Wang, M; Whitmore, J J; Whyte, J; Wichmann, K; Wick, K; Wiggers, L; Wills, H H; Wing, M; Wlasenko, M; Wolf, G; Yagues-Molina, A G; Yamada, S; Yamazaki, Y; Yoshida, R; Youngman, C; Zambrana, M; Zawiejski, L; Zeuner, W; Zhautykov, B O; Zhou, C; Zichichi, A; Ziegler, A; Zotkin, D S; Zotkin, S A; De Favereau, J; De Wolf, E; Del Peso, J
2005-01-01
Exclusive electroproduction of $\\phi$ mesons has been studied in $e^\\pm p$ collisions at $\\sqrt{s}=318 \\gev$ with the ZEUS detector at HERA using an integrated luminosity of 65.1 pb$^{-1}$. The $\\gamma^*p$ cross section is presented in the kinematic range $2mesons. The ratios $R$ of the cross sections for longitudinally and transversely polarized virtual photons are presented as functions of $Q^2$ and $W$. The data are also compared to predictions from theoretical models.
Nonequilibrium meson production in strong fields
Juchnowski, L; Fischer, T; Smolyansky, S A
2015-01-01
We develop a kinetic equation approach to nonequilibrium pion and sigma meson production in a time-dependent, chiral symmetry breaking field (inertial mechanism). We investigate the question to what extent the low-momentum pion enhancement observed in heavy-ion collisions at CERN - LHC can be addressed within this formalism. In a first step, we consider the inertial mechanism for nonequilibrium production of $\\sigma-$mesons and their simultaneous decay into pion pairs for two cases of $\\sigma$ mass evolution. The resulting pion distribution shows a strong low-momentum enhancement which can be approximated by a thermal Bose distribution with a chemical potential that appears as a trace of the nonequilibrium process of its production.
Glueballs and vector mesons at NICA
Parganlija, Denis
2016-01-01
Two interconnected fields of interest are suggested for NICA. Firstly, existence of glueballs is predicted by the theory of strong interaction but -- even after decades of research -- glueball identification in the physical spectrum is still unclear. NICA can help to ascertain experimental glueball candidates via J/Psi decays whose yield is expected to be large. Importance of glueballs is not limited to vacuum: since they couple to other meson states, glueballs can also be expected to influence signatures of chiral-symmetry restoration in the high-energy phase of strong dynamics. Mass shifting or in-medium broadening of vector and axial-vector mesons may occur there but the extent of such phenomena is still uncertain. Additionally, glueball properties could also be modified in medium. Exploration of these issues is the second suggested field of interest that can be pursued at NICA.
QCD monopole and sigma meson coupling
Iwazaki, Aiichi
2016-01-01
Under the assumption of the Abelian dominance in QCD, we show that chiral condensate is locally present around a QCD monopole. The appearance of the chiral condensate around a GUT monopole was shown in the previous analysis of the Rubakov effect. We apply a similar analysis to the QCD monopole. It follows that the condensation of the monopole carrying the chiral condensate leads to the chiral symmetry breaking as well as quark confinement. To realize the result explicitly, we present a phenomenological linear sigma model coupled with the monopoles, in which the monopole condensation causes the chiral symmetry breaking as well as confinement. The monopoles are assumed to be described by a model of dual superconductor. We identify the monopoles with scalar isoscalar $f_0$ mesons with masses $1400\\sim 1700$ MeV as well as dual gauge fields with $h_1$ vector mesons with masses $\\sim 1500$MeV.
Exploring $X(5568)$ as a meson molecule
Agaev, S S; Sundu, H
2016-01-01
The parameters, i.e. the mass and decay constant of the exotic $X_b(5568)$ state newly observed by D0 Collaboration, as well as the decay width of the process $X_b \\to B_s^{0}\\pi^{+}$ are explored using $B\\overline{K}$ molecule assumption on its structure. Computational methods employed here encompass QCD two-point and light-cone sum rules, latter being considered in the soft-meson approximation. The obtained results are compared with the data of the D0 Collaboration, as well as with the predictions of the diquark-antidiquark model. This comparison strengthens the diquark-antidiquark picture for the $X_b(5568)$ state rather than a meson molecule structure.
Meson exchange and neutral weak currents
Measurements of parity-violating electron scattering asymmetries to determine weak neutral currents in nuclei will be effected by the presence of meson exchange currents. Present low momentum transfer calculations, based on a flavor independent framework, show these effects to be small. In general, however, as the momentum transfer increases to values typical of deep-inelastic scattering, fragmentation functions show a clear flavor dependence. It is suggested that a good experimental starting point for understanding the flavor dependence of meson production and exchange currents is the Q2 dependence of parity-violating asymmetry in inclusive single pion electroproduction. A CEBAF facility with doubled energy is necessary to approach momentum transfers where this process begins to scale
Vector mesons in strongly interacting matter
Volker Metag
2010-08-01
Properties of hadrons in strongly interacting matter provide a link between quantum chromodynamics in the strong coupling regime and experimental observables. QCD sum rules show that changes in chiral and higher-order condensates, partially associated with a restoration of chiral symmetry in the nuclear medium, will lead to significant changes in the low-energy spectrum of hadrons. Heavy-ion collisions and reactions with elementary probes have been used to extract experimental information on in-medium properties of hadrons. Results on the light vector mesons ρ, , and , are summarized and compared. Almost all experiments report a softening of the spectral functions with increases in width depending on the density and temperature of the hadronic environment. No evidence for mass shifts is found in majority of the experiments. Remaining inconsistencies among experimental results demonstrate the need for further measurements with higher statistics and inrceased acceptance in particular for low-momentum vector mesons.
Diffractive hadronic production of D mesons
A search for charmed D mesons was made with a 217 GeV π- beam on a liquid hydrogen target. The Chicago Cyclotron Spectrometer at Fermilab was used to analyze the hadronic decay of a D meson in coincidence with a prompt muon and a recoil proton. A total of 50 +- 12 D+- events were observed with equal numbers in the two channels K+-π-+π-+. Some of the cuts selected diffractive events. When these cuts were removed the signal remained the same, although the background was greatly increased. The Feynman X and angular distributions were consistent with diffractive production. A diffractive model yielded a cross section of (6 to 10) +- 4 μb
Meson exchange and neutral weak currents
Beck, D.H. [Univ. of Illinois, Urbana, IL (United States)
1994-04-01
Measurements of parity-violating electron scattering asymmetries to determine weak neutral currents in nuclei will be effected by the presence of meson exchange currents. Present low momentum transfer calculations, based on a flavor independent framework, show these effects to be small. In general, however, as the momentum transfer increases to values typical of deep-inelastic scattering, fragmentation functions show a clear flavor dependence. It is suggested that a good experimental starting point for understanding the flavor dependence of meson production and exchange currents is the Q{sup 2} dependence of parity-violating asymmetry in inclusive single pion electroproduction. A CEBAF facility with doubled energy is necessary to approach momentum transfers where this process begins to scale.
Rotational Spectra of the Baryons and Mesons
Akers, D
2003-01-01
An investigation of the rotational spectra of baryons and mesons is conducted. Diakonov, Petrov and Polyakov claimed that all light baryons are rotational excitations. A study of the history of particle physics indicates that the ideas of rotational spectra can be originally attributed to a constituent-quark (CQ) model as proposed by Mac Gregor. Later research advanced spin-orbit splitting in a deformed model as suggested by Bhaduri and others. In the present work, we show from current data that the rotational spectra of baryons and mesons are in agreement with the original claims of Mac Gregor: namely, the values for the rotational energies Erot of particles merge with those of nuclear rotational bands in light nuclei. It is also shown that particles of different isotopic spins are separated in mass by a 70 MeV quantum, which is related to the SU(3) decuplet mass spacing as originally proposed by Gell-Mann.
LHCb: LHCb results on $B$ meson mixing
Eitschberger, U
2013-01-01
On the poster three LHCb results on B meson mixing using a datasample of 1 fb$^{-1}$ of $pp$ collisions at $\\sqrt{s} =$ 7 TeV are presented. The B meson oscillation frequencies are measured as $\\Delta m_d = 0.5156 \\pm 0.0051 (\\text{stat}) \\pm 0.0033 (\\text{syst}) \\text{ps}^{-1}$ and $\\Delta m_s = 17.768 \\pm 0.023 (\\text{stat}) \\pm 0.006 (\\text{syst}) \\text{ps}^{-1}$. The CP violation observables in the decay channel $B^0 \\rightarrow J/\\psi K^0_S$ are determined as $S_{J/\\psi K^0_S} = 0.73 \\pm 0.07 (\\text{stat})\\pm 0.04 (\\text{syst})$ and $C_{J/\\psi K^0_S} = 0.03 \\pm 0.09 (\\text{stat})\\pm 0.01 (\\text{syst})$.
Antinucleon nucleon annihilations into two mesons
We study two aspects of the antinucleon-nucleon annihilation into two mesons (antiNN → M1M2), starting from simple Born diagrams. On one hand, we discuss the possibility of modelling the antiNN optical potential with the box diagrams related to the M1M2 channels. We include the lightest pseudoscalar, scalar and vector mesons with effective coupling constants. Much more channels appear to be needed in order to achieve sensible results. On the other hand, we show that a simple phenomenological optical potential, successfull in reproducing antiNN elastic scattering and total annihilation data can be further used to make predictions on the antiNN → M1M2 processes, which prove to be in good agreement with experiment. We find a lower bound of 17% on the relative contribution of these reactions to the antiNN annihilation. Also, the model favours a rather small effective radius for the nucleon
Electroproduction of tensor mesons in QCD
Braun, V. M.; Kivel, N.; Strohmaier, M.; Vladimirov, A. A.
2016-06-01
Due to multiple possible polarizations hard exclusive production of tensor mesons by virtual photons or in heavy meson decays offers interesting possibilities to study the helicity structure of the underlying short-distance process. Motivated by the first measurement of the transition form factor γ∗γ → f 2(1270) at large momentum transfers by the BELLE collaboration we present an improved QCD analysis of this reaction in the framework of collinear factorization including contributions of twist-three quark-antiquark-gluon operators and an estimate of soft end-point corrections using light-cone sum rules. The results appear to be in good agreement with the data, in particular the predicted scaling behavior is reproduced in all cases.
Electroproduction of tensor mesons in QCD
Braun, V M; Strohmaier, M; Vladimirov, A A
2016-01-01
Due to multiple possible polarizations hard exclusive production of tensor mesons by virtual photons or in heavy meson decays offers interesting possibilities to study the helicity structure of the underlying short-distance process. Motivated by the first measurement of the transition form factor $\\gamma^*\\gamma \\to f_2(1270)$ at large momentum transfers by the BELLE collaboration we present an improved QCD analysis of this reaction in the framework of collinear factorization including contributions of twist-three quark-antiquark-gluon operators and an estimate of soft end-point corrections using light-cone sum rules. The results appear to be in a very good agreement with the data, in particular the predicted scaling behavior is reproduced in all cases.
Polarization observables in φ-meson photoproduction
We analyze polarization observables of the φ-meson photoproduction from a proton within the uud-ss bar cluster model as a probe of strangeness in the proton. Our consideration is based on the relativistic quark model that takes into account the Lorentz-contraction effects of the intrinsic hadron wave functions. We show that transverse target-recoil and longitudinal beam-target double polarizations in the diffractive vector meson dominance model are different from those of the knockout mechanisms and the difference between them is as much as 20∼80% if only 0.2∼0.3% strangeness admixture in proton wave function is assumed. This strong effect may be studied experimentally. 17 refs., 4 figs
LAMPF: the meson factory. A LASL monograph
Allred, J.C.
1977-08-01
A general and simplified introduction to the entire concept of LAMPF is given in terms of its experimental capabilities. Parts of the current experimental program are used as illustrative examples. Topics discussed include: (1) the evolution of the meson factory; (2) accelerator construction; (3) strong focusing; (4) accelerator innovations at LAMPF; (5) photons and pions; (6) muons as nuclear probes; (7) nuclear chemistry; (8) radiobiology and medical applications; (9) radioisotope production; (10) materials testing; and (11) LAMPF management and users group. (PMA)
Radiative widths of K and rho mesons
The dissociation of K and π mesons in the nuclear Coulomb field has been studied. Results are: GAMMA(rho→πγ) = 67 +- 7 KeV., GAMMA(K*(890)→Kπ) = 60 +- 15 KeV; and the observation of Coulomb excitation of the following states: K*(1420,1700),A2,A1,B. The measured widths are in rough agreement with a simple quark model
Non-conventional mesons at PANDA
Giacosa, Francesco
2015-04-01
Non-conventional mesons, such as glueballs and tetraquarks, will be in the focus of the PANDA experiment at the FAIR facility. In this lecture we recall the basic properties of QCD and describe some features of unconventional states. We focus on the search of the not-yet discovered glueballs and the use of the extended Linear Sigma Model for this purpose, and on the already discovered but not-yet understood X, Y, Z states.
B meson physics and related new physics
We have surveyed the some models focusing on the mixings, the CP violation and the rare decay in the B meson system. The ARGUS data of the Bd0-B-bard0 mixing gives us some constraints as to parameters of these models. Especially, we have investigated the composite scale in detail using the ARGUS data of the Bd0-B-bard0 mixing and obtained some interesting results. (author)
In expectation of imminent results from the new hyperon beam experiment at CERN concerning the exotic U-meson at 3.1 GeV, we propose a detailed program of experimental tests to check the suggestion that U is a qqq-barq-bar ''M-diquonium'' state. Apart from some very characteristic decay modes, the U is expected to occur together with several analogous states with various quantum numbers to which it is intimately related. (author)
Non-perturbative effects in heavy mesons
The existence of a non-trivial vacuum has influences on bound states. We calculate its effects on heavy pseudoscalar mesons parameterizing the non-perturbative properties by gluon condensates and using a non-relativistic approximation. We derive and effective Hamiltonian taking into account the interaction with the gluonic vacuum. The background gauge formalism used preserves gauge invariance. Non-perturbative effects are shown to be more important in higher excited states. (author)
Bubble chamber: D meson production and decay
1978-01-01
This event shows real particle tracks from the Big European Bubble Chamber (BEBC), which was used to observe neutrino and hadron beams between 1973 and 1984 from the PS and SPS accelerators. In this event a neutrino interacts with a proton producing an excited D meson. A labeled diagram is seen on the right as the particles spiral in the magnetic field of the detector.
Understanding the baryon and meson spectra
Pennington, Michael R. [JLAB
2013-10-01
A brief overview is given of what we know of the baryon and meson spectra, with a focus on what are the key internal degrees of freedom and how these relate to strong coupling QCD. The challenges, experimental, theoretical and phenomenological, for the future are outlined, with particular reference to a program at Jefferson Lab to extract hadronic states in which glue unambiguously contributes to their quantum numbers.
Leading logarithms for mesons and nucleons
Bijnens, Johan; Kampf, Karol; Vladimirov, Alexey
2015-01-01
This talk describes the work done in calculating leading logarithms in massive effective field theories. We discuss shortly leading logarithms in renormalizable theories and how they can be calculated using only one-loop calculations in effective field theories. The remainder of the talk discusses masses, decay constants, condensates and anomalous processes in mesonic effective field theories like Chiral Perturbation Theory and the expansion of the nucleon mass.
Euclidean fields: vector mesons and photons
Free transverse vector fields of mass >= 0 are studied. The model is related to the usual free vector meson and electromagnetic quantum field theories by extension of the field operators from transverse to arbitrary test functions. The one-particle states in transverse gauge and their localization are described. Reflexion positivity is proved and derived are free Feynman-Kac-Nelson formulas. An Euclidean approach to a photon field in a spherical world using dilatation covariance and inversions is given
Vector meson production from a polarized nucleon
We provide a framework to analyze the electroproduction process ep→epρ with a polarized target, writing the angular distribution of the ρ decay products in terms of spin density matrix elements that parameterize the hadronic subprocess γ*p → ρp. Using the helicity basis for both photon and meson, we find a representation in which the expressions for a polarized and unpolarized target are related by simple substitution rules. (orig.)
Vector meson contributions in ε'/ε
The CP-violating parameter -bar '/-bar is computed using the low-energy dynamics of the chiral theory supplemented by vector resonances. The divergent contributions coming from strong π-π scattering are tamed by vector-meson exchange terms. This amounts to softening the fast growing high-energy behaviour of π-π scattering. The final result for ε'/ε shows a smooth dependence on the cut-off where low energy dynamics is matched with that of QCD
Exclusive hadronic decays of B mesons
Using the ARGUS detector at the e+e- storage ring DORIS II, we have measured B decays into exclusive final states containing a D or D* meson plus several pions, or containing a J/ψ or ψ' meson plus a strange particle. Some of these channels have not been seen before, while others represent updated measurements of previous results. The branching ratios are compared with the predictions of the model of Bauer, Stech and Wirbel. Using the cleanest decay channels, the mass of the charged and neutral B meson are found to be msub(B-)=(5280.5±1.0±2.0) MeV/c2 and msub(B0)=(5279.6±0.7±2.0) MeV/c2 respectively, yielding a mass difference msub(B0)-msub(B-)=(-0.9±1.2±0.5) MeV/c2. (orig.)
Leptonic Decays of Charged Pseudoscalar Mesons - 2015
Rosner, Jonathan L; Van de Water, Ruth S
2015-01-01
We review the physics of purely leptonic decays of $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ pseudoscalar mesons. The measured decay rates are related to the product of the relevant weak-interaction-based CKM matrix element of the constituent quarks and a strong interaction parameter related to the overlap of the quark and antiquark wave-functions in the meson, called the decay constant $f_P$. The leptonic decay constants for $\\pi^\\pm$, $K^\\pm$, $D^{\\pm}$, $D_s^\\pm$, and $B^\\pm$ mesons can be obtained with controlled theoretical uncertainties and high precision from {\\it ab initio} lattice-QCD simulations. The combination of experimental leptonic decay-rate measurements and theoretical decay-constant calculations enables the determination of several elements of the CKM matrix within the standard model. These determinations are competitive with those obtained from semileptonic decays, and also complementary because they are sensitive to different quark flavor-changing currents. They can also be use...
Κ-meson decays and parity violation
Between 1948 and 1954 many Κ-meson decay modes were observed, including the tau, pion and xi positives, in emulsion experiments all with masses around 500 MeV. An attempt was made to rationalize the various names for the new particles being discovered. A period of experimental consolidation followed. An attempt was then made to determine the spin parity of the three-pion system from tau plus decay using matrix calculations. New stripped emulsion techniques now permitted a secondary-particle track to be followed to its endpoint. Stacked emulsions were flown in balloons to study Κ mesons and hyperons using cosmic radiation. Later similar work used the new particle accelerators, the Cosmotron and the Bevatron as sources. The author showed that the tau plus and theta plus were competing decay modes of the same Κ+ meson, but this meant that parity conservation was violated. Later theoreticians T D Lee and C N Yang provided evidence for this surprising idea from their work on semileptonic weak interactions. (UK)
Holographic Picture of Heavy Vector Meson Melting
Braga, Nelson R F; Diles, Saulo
2016-01-01
The fraction of heavy vector mesons produced in a heavy ion collision, as compared to a proton proton collision, serves as an important indication of the formation of a thermal medium, the quark gluon plasma. This sort of analysis strongly depends on understanding the thermal effects of a medium like the plasma on the states of heavy mesons. In particular, it is crucial to know the temperature ranges where they undergo a thermal dissociation, or melting. AdS/QCD models are know to provide an important tool for the calculation of hadronic masses, but in general are not consistent with the observation that decay constants of heavy vector mesons decrease with excitation level. It has recently been shown that this problem can be overcome using a soft wall background and introducing an extra energy parameter, through the calculation of correlation functions at a finite position of anti-de Sitter space. This approach leads to the evaluation of masses and decay constants of S wave quarkonium states with just one fla...
Meson F1 spin and parity measurement
Data of several series of antiproton-proton annihilation events produced at 1,1 to 2,04 GeV/c are analyzed. The meson resonances three-body disintegration (KantiKπ) and particularly the F1 meson of which quantum numbers spin and parity were not quite determinated, were studied. In the antiproton-proton reaction, it was possible to put into evidence the F1 meson existence. To test the spin, in this experiment were used the following processes: the 'angular correlation' test using the production of F1 associated with the omega as well as the desintegrations in series F1→K*K, K*→Kπ; the 'positivity' test which are directly bound to the positivity conditions of the F1 polarization density operator and use only F1→K*K desintegration. The coherence in the measures obtained in several independent tests allowed to conclude with a good experimental evidence that the spin-parity hypothesis Jsub(F1)sup(P)=2- is the most probable
Decays of mesons with charm quarks on the lattice
We investigate mesons containing charm quarks on fine lattices with a-1 ∝ 5 GeV. The quenched approximation is employed using theWilson gauge action at β = 6.6 and nonperturbatively O(a) improvedWilson quarks. We present results for decay constants using various interpolating fields and give preliminary results for form factors of semileptonic decays of Ds mesons to light pseudoscalar mesons. (orig.)
Spin O decay angular distribution for interfering mesons in electroproduction
Self analyzing meson electroproduction experiments are currently being planned for the CEBAF CLAS detector. These experiments deduce the spin polarization of outgoing unstable spin s (?)0 mesons from their decay angular distribution, W(θ,ψ). The large angular acceptance of the CLAS detector permits kinematic tracking of a sufficient number of these events to accurately determine electroproduction amplitudes from the deduced polarization. Maximum polarization information is obtained from W(θ,ψ) for decay into spin 0 daughters. The helicity of the decaying meson is transferred to the daughter's relative orbital angular momentum m-projection; none is open-quotes absorbedclose quotes into daughter helicities. The decaying meson's helicity maximally appears in W(θ,ψ). W(θ,ψ) for spin 0 daughters has been derived for (1) vector meson electroproduction and (2) general interfering mesons produced by incident pions. This paper derives W(θ,ψ) for electroproduction of two interfering mesons that decay into spin 0 daughters. An application is made to the case of interfering scalar and vector mesons. The derivation is an extension of work by Schil using the general decay formalism of Martin. The expressions can be easily extended to the case of N interfering mesons since interference occurs pairwise in the observable W (θ,ψ), a quadratic function of the meson amplitudes. The derivation uses the virtual photon density matrix of Schil which is transformed by a meson electroproduction transition operator, T. The resulting density matrix for the interfering mesons is then converted into a corresponding statistical tensor and contracted into the efficiency tensor for spin 0 daughters
Inclusive spectra of hadrons in B-meson decays
The inclusive spectra of hadrons (mainly pions) produced in the semileptonic and nonleptonic decays of B-mesons are calculated. Parameters of spectra for different types of hard qq-bar-strings, appearing in the B-meson decays, are determined using the data on e+e-annihilation. Numerical results for B-meson decay induced by both b→b and b→u transitions are presented. 10 refs.; 5 figs
Open flavour charmed mesons in a quantum chromodynamics potential model
Krishna Kingkar Pathak; D K Choudhury
2012-12-01
We modify the mesonic wave function by using a short distance scale 0 in analogy with hydrogen atom and estimate the values of masses and decay constants of the open flavour charm mesons , $D_{s}$ and $B_{c}$ within the framework of a QCD potential model. We also calculate leptonic decay widths of these mesons to study branching ratios and lifetime. The results are in good agreement with experimental and other theoretical values.
Central exclusive meson pair production in the perturbative regime
Harland-Lang, L A; Ryskin, M G; Stirling, W J
2011-01-01
We present a study of the central exclusive production (CEP) of meson pairs, MMbar, at sufficiently high invariant mass that a perturbative QCD formalism is applicable. Within this framework, MMbar production proceeds via the gg --> MMbar hard scattering sub-process, which can be calculated within the hard exclusive formalism. We present explicit calculations for the gg --> MMbar helicity amplitudes for different meson states and, using these, show results for meson pair CEP in the perturbative regime.
Hadronic D and D_s Meson Decays
Ryd, Anders
2009-01-01
We provide a comprehensive review of hadronic decays of D and D_s mesons. We discuss current theoretical and experimental challenges and successes in understanding of hadronic transitions of those mesons. A brief overview of the theoretical and experimental tools are given before discussing the absolute branching fractions for D and D_s mesons. Cabibbo suppressed and rare hadronic decays are discussed and compared with theory before discussing our understanding of hadronic multibody decays.
Chiral phase transition scenarios from the vector meson extended Polyakov quark meson model
Kovács, Péter
2015-01-01
Chiral phase transition is investigated in an $SU(3)_L \\times SU(3)_R$ symmetric vector meson extended linear sigma model with additional constituent quarks and Polyakov loops (extended Polyakov quark meson model). The parameterization of the Lagrangian is done at zero temperature in a hybrid approach, where the mesons are treated at tree-level, while the constituent quarks at 1-loop level. The temperature and baryochemical potential dependence of the two assumed scalar condensates are calculated from the hybrid 1-loop level equations of states. The order of the phase transition along the $T=0$ and $\\mu_B=0$ axes are determined for various parameterization scenarios. We find that in order to have a first order phase transition at $T=0$ as a function of $\\mu_B$ a light isoscalar particle is needed.
The Meson Spectroscopy Program at the Jefferson Laboratory
Filippi, Alessandro [Istituto Nazionale di Fisica Nucleare (INFN), Torino (Italy). et al.
2015-06-01
The experimental techniques that will be applied by the next generation meson spectroscopy experiments at JLab are described. For the first time, these experiments will be able to exploit the features of a photon beam of unprecedented intensity and momentum resolution, that will allow to perform precision studies of meson states with masses below 3 GeV/c^{2}. Photon induced reactions will enhance the production of spin-1 mesons, that are of particular interest according to the most recent Lattice QCD calculations of the lightest exotic hybrid meson.
Scattering amplitudes to all orders in meson exchange
As the number of colors in QCD, NC, becomes large, it is possible to sum up all meson-exchange contributions, however arbitrarily complicated, to meson-baryon and baryon-baryon scattering. A semi-classical structure for the two-flavor theory emerges, in close correspondence to vector-meson-augmented Skyrme models. In this limit, baryons act as extended static sources for the classical meson fields. This leads to non-linear differential equations for the classical meson fields which can be solved numerically for static radial (hedgehog-like) solutions. The non-linear terms in the equations of motion for the quantized meson fields can then be simplified, to leading order in 1/NC, by replacing all factors of the meson field but one by the previously-found classical field. This results in linear, Schroedinger-like equations, which are easily solved. For the meson-baryon case the solution can be subsequently analyzed to obtain the phase shifts for the scattering and, from these, the baryon resonance spectrum of the model. As the warm-up, we have carried out this calculation for the simple case of σ mesons only, finding sensible results. 8 refs., 3 figs
Mesons in Nuclei and Partial Restoration of Chiral Symmetry
Jido, Daisuke
2016-01-01
Recent topics on mesons in nuclei are discussed by especially emphasizing the role of the partial restoration of chiral symmetry in the nuclear medium. The spontaneously broken chiral symmetry in vacuum is considered to be incompletely restored in finite nuclear density systems with moderate reduction of the magnitude of the quark condensate. On the partial restoration of chiral symmetry, the wave function renormalization is important to be taken into account for the Nambu-Goldstone bosons. We also discuss the possible change of the meson properties in the nuclear medium and meson-nucleus systems for the $\\bar K$, $\\eta$, $K^{+}$ and $\\eta^{\\prime}$ mesons.
Search for medium modifications of the rho meson.
Nasseripour, R; Wood, M H; Djalali, C; Weygand, D P; Tur, C; Mosel, U; Muehlich, P; Adams, G; Amaryan, M J; Ambrozewicz, P; Anghinolfi, M; Asryan, G; Avakian, H; Bagdasaryan, H; Baillie, N; Ball, J P; Baltzell, N A; Barrow, S; Battaglieri, M; Bedlinskiy, I; Bektasoglu, M; Bellis, M; Benmouna, N; Berman, B L; Biselli, A S; Blaszczyk, L; Bouchigny, S; Boiarinov, S; Bradford, R; Branford, D; Briscoe, W J; Brooks, W K; Bültmann, S; Burkert, V D; Butuceanu, C; Calarco, J R; Careccia, S L; Carman, D S; Carnahan, B; Casey, L; Chen, S; Cole, P L; Collins, P; Coltharp, P; Crabb, D; Crannell, H; Crede, V; Cummings, J P; Dashyan, N; De Masi, R; De Vita, R; De Sanctis, E; Degtyarenko, P V; Denizli, H; Dennis, L; Deur, A; Dharmawardane, K V; Dickson, R; Dodge, G E; Doughty, D; Dugger, M; Dytman, S; Dzyubak, O P; Egiyan, H; Egiyan, K S; El Fassi, L; Elouadrhiri, L; Eugenio, P; Fedotov, G; Feldman, G; Feuerbach, R J; Funsten, H; Garçon, M; Gavalian, G; Gilfoyle, G P; Giovanetti, K L; Girod, F X; Goetz, J T; Gordon, C I O; Gothe, R W; Griffioen, K A; Guidal, M; Guler, N; Guo, L; Gyurjyan, V; Hadjidakis, C; Hafidi, K; Hakobyan, H; Hakobyan, R S; Hanretty, C; Hardie, J; Hersman, F W; Hicks, K; Hleiqawi, I; Holtrop, M; Hyde-Wright, C E; Ilieva, Y; Ireland, D G; Ishkhanov, B S; Isupov, E L; Ito, M M; Jenkins, D; Jo, H S; Johnstone, J R; Joo, K; Juengst, H G; Kalantarians, N; Kellie, J D; Khandaker, M; Kim, W; Klein, A; Klein, F J; Klimenko, A V; Kossov, M; Krahn, Z; Kramer, L H; Kubarovsky, V; Kuhn, J; Kuhn, S E; Kuleshov, S V; Lachniet, J; Laget, J M; Langheinrich, J; Lawrence, D; Li, Ji; Livingston, K; Lu, H Y; Maccormick, M; Markov, N; Mattione, P; McAleer, S; McKinnon, B; McNabb, J W C; Mecking, B A; Mehrabyan, S; Melone, J J; Mestayer, M D; Meyer, C A; Mibe, T; Mikhailov, K; Minehart, R; Mirazita, M; Miskimen, R; Mokeev, V; Moriya, K; Morrow, S A; Moteabbed, M; Mueller, J; Munevar, E; Mutchler, G S; Nadel-Turonski, P; Niccolai, S; Niculescu, G; Niculescu, I; Niczyporuk, B B; Niroula, M R; Niyazov, R A; Nozar, M; Osipenko, M; Ostrovidov, A I; Park, K; Pasyuk, E; Paterson, C; Anefalos Pereira, S; Pierce, J; Pivnyuk, N; Pocanic, D; Pogorelko, O; Pozdniakov, S; Preedom, B M; Price, J W; Prok, Y; Protopopescu, D; Raue, B A; Riccardi, G; Ricco, G; Ripani, M; Ritchie, B G; Ronchetti, F; Rosner, G; Rossi, P; Sabatié, F; Salamanca, J; Salgado, C; Santoro, J P; Sapunenko, V; Schumacher, R A; Serov, V S; Sharabian, Y G; Sharov, D; Shvedunov, N V; Smith, E S; Smith, L C; Sober, D I; Sokhan, D; Stavinsky, A; Stepanyan, S S; Stepanyan, S; Stokes, B E; Stoler, P; Strakovsky, I I; Strauch, S; Taiuti, M; Tedeschi, D J; Tkabladze, A; Tkachenko, S; Todor, L; Ungaro, M; Vineyard, M F; Vlassov, A V; Watts, D P; Weinstein, L B; Williams, M; Wolin, E; Yegneswaran, A; Zana, L; Zhang, B; Zhang, J; Zhao, B; Zhao, Z W
2007-12-31
The photoproduction of vector mesons on various nuclei has been studied using the CLAS detector at Jefferson Laboratory. The vector mesons, rho, omega, and varphi, are observed via their decay to e;{+}e;{-}, in order to reduce the effects of final-state interactions in the nucleus. Of particular interest are possible in-medium effects on the properties of the rho meson. The rho mass spectrum is extracted from the data on various nuclei, 2H, C, Fe, and Ti. We observe no significant mass shift and some broadening consistent with expected collisional broadening for the rho meson. PMID:18233570
Deep inelastic scattering operators in meson-nucleon theory
Nonrelativistic meson-nucleon theory of deep-inelastic scattering (DIS) of leptons on the deuteron is considered. Explicit expressions of nonrelativistic composed operators of DIS in the framework of the operator product expansion method are obtained in terms of interacting meson-nucleon fields. An analytic expression of the second moment of the structure functions (up to g2 accuracy( is obtained with particular emphasis on self-energy contributions and meson exchange currents (MEC). Deuteron moments are shown to be expressed in terms of constituent (nucleons and mesons) observables. The energy conservation law is restored by taking into account MEC
Search for gluonic excitations in light unconventional mesons
Paul Eugenio
2007-07-01
Studies of meson spectra via strong decays provide insight regarding QCD at the confinement scale. These studies have led to phenomenologicalmodels for QCD such as the constituent quark model. However, QCD allows for a much richer spectrum of meson states which include extra states such as exotics, hybrids, multi-quarks, and glueballs. First discussion of the status of exotic meson searches is given followed by a discussion of plans at Jefferson Lab to double the energy of the machine to 12 GeV, which will allow us to access photoproduction of mesons in search for gluonic excited states.
Meson masses and decay constants from unquenched lattice QCD
We report results for the masses of the flavour non-singlet light 0++, 1--, and 1+- mesons from unquenched lattice QCD at two lattice spacings. The twisted mass formalism was used with two flavours of sea quarks. For the 0++ and 1+- mesons we look for the effect of decays on the mass dependence. For the light vector mesons we study the chiral extrapolations of the mass. We report results for the leptonic and transverse decay constants of the meson. We test the mass dependence of the KRSF relations. (orig.)
Heavy mesons in a hadronic medium: interaction and transport coefficients
Torres-Rincon, Juan M; Cabrera, Daniel; Romanets, Olena; Tolos, Laura
2015-01-01
We review the recent results of heavy meson diffusion in thermal hadronic matter. The interactions of D and B-bar mesons with other hadrons (light mesons and baryons) are extracted from effective field theories based on chiral and heavy-quark symmetries. When these guiding principles are combined with exact unitarity, physical values of the cross sections are obtained. These cross sections (which contain resonant contributions) are used to calculate the drag and diffusion coefficients of heavy mesons immersed in a thermal and dense medium. The transport coefficients are computed using a Fokker-Planck reduction of the Boltzmann equation.
NN-bar vacuum polarization and nuclear meson exchange interactions
The relativistic Hartree equations for a finite nucleus are solved taking into account negative energy nucleons. This formulation yields the nuclear mean meson fields suppressed and the nuclear radius increased owing to the contribution of negative energy nucleons. Secondly, taking the positive energy nucleon sector picture of a nucleus, we derive the nuclear meson exchange interactions between positive energy nucleons modified by the NN-bar vacuum polarization on the cause of the meson exchanges. The vacuum polarization suppresses the meson exchange interactions and increases the interaction ranges. (author)
The hybrid mesons quest: the MesonEx experiment at Jefferson Laboratory
Rizzo, Alessandro [Univ. of Rome Tor Vergata (Italy)
2016-03-01
The meson spectroscopy plays nowadays a central role in the investigation of hadron structure thanks to the possible existence of exotic hybrid mesons, quark-antiquark-gluon bound states. Their explicit gluonic degrees of freedom which should clearly emerge from a Partial Wave Analysis (PWA) of the corresponding Dalitz plot of the exotic particle decay, may result in final JPC configurations not allowed in the constituent quark model. Besides this clear signature, hybrid mesons are also expected to have a large particle multiplicity decays, requiring for their search an experimental apparatus with high performances in terms of rate capability, resolution and almost a full acceptance to apply PWA methods. New-generation experiments are planned at Thomas Jefferson National Laboratory (VA, USA) for which an unprecedented statistics of large multiplicity decay events with fully reconstructed kinematics will be available. In particular for the MesonEx (CLAS12) experiment in Hall B, a wide scientific program that will start in 2016 has been deployed to study the meson spectrum at energies up to 11 GeV. A key role in such program is played by the Forward Tagger apparatus of the experiment, which will allow to extend the study of meson electro-production to very low Q2 values, in a quasi-real photo production kinematical region, where the production of hybrid mesons is expected to be favorite. Currently a new analysis framework for the search of the hybrid mesons is being set up by the HASPECT network, an international structure which gather people involved into theoretical and experimental hadronic physics all over the world. The goals of the network is to develop new analysis models and statistical techniques to unfold the signal and background distributions in high-statistics datasets. In this work are briefly presented the first preliminary results from the application of a statistical technique, namely the sPlot, to the data already acquired by the CLAS experiment for
The hybrid mesons quest: the MesonEx experiment at Jefferson Laboratory
Rizzo, A.; CLAS Collaboration
2016-02-01
The meson spectroscopy plays nowadays a central role in the investigation of hadron structure thanks to the possible existence of exotic hybrid mesons, quark-antiquark-gluon bound states. Their explicit gluonic degrees of freedom which should clearly emerge from a Partial Wave Analysis (PWA) of the corresponding Dalitz plot of the exotic particle decay, may result in final JPC configurations not allowed in the constituent quark model. Besides this clear signature, hybrid mesons are also expected to have a large particle multiplicity decays, requiring for their search an experimental apparatus with high performances in terms of rate capability, resolution and almost a full acceptance to apply PWA methods. New-generation experiments are planned at Thomas Jefferson National Laboratory (VA, USA) for which an unprecedented statistics of large multiplicity decay events with fully reconstructed kinematics will be available. In particular for the MesonEx (CLAS12) experiment in Hall B, a wide scientific program that will start in 2016 has been deployed to study the meson spectrum at energies up to 11 GeV. A key role in such program is played by the Forward Tagger apparatus of the experiment, which will allow to extend the study of meson electro-production to very low Q2 values, in a quasi-real photo production kinematical region, where the production of hybrid mesons is expected to be favorite. Currently a new analysis framework for the search of the hybrid mesons is being set up by the HASPECT network, an international structure which gather people involved into theoretical and experimental hadronic physics all over the world. The goals of the network is to develop new analysis models and statistical techniques to unfold the signal and background distributions in high-statistics datasets. In this work are briefly presented the first preliminary results from the application of a statistical technique, namely the sPlot, to the data already acquired by the CLAS experiment for
This paper introduces the current state of studies on the binding system between π meson/ η meson/ η(958) meson, and nuclei. Experimental studies on π meson atoms have been carried out by injecting π mesons with low energy into materials. Currently, a high accuracy of π meson atomic spectroscopy has been achieved based on (d, 3He) reaction, and studies on π meson atoms are developing through the systematic study on a number of binding states in various nuclei. As the characteristics of the system of η meson atomic nuclei, the strong bond between ηN and N*(1535) is picked up. In the model describing the resonance N*(1535), there are a chiral doublet model and chiral unitary model. The mass origin of η(958) meson is considered due to UA(1) quantum anomaly effect. When the change in mass in nucleus has been observed, it is expected to obtain information on the changes in the contribution of UA(1) quantum anomaly to the mass. (A.O.)
In-medium QCD sum rules for {omega} meson, nucleon and D meson
Thomas, Ronny
2008-07-01
The modifications of hadronic properties caused by an ambient nuclear medium are investigated within the scope of QCD sum rules. This is exemplified for the cases of the {omega} meson, the nucleon and the D meson. By virtue of the sum rules, integrated spectral densities of these hadrons are linked to properties of the QCD ground state, quantified in condensates. For the cases of the {omega} meson and the nucleon it is discussed how the sum rules allow a restriction of the parameter range of poorly known four-quark condensates by a comparison of experimental and theoretical knowledge. The catalog of independent four-quark condensates is covered and relations among these condensates are revealed. The behavior of four-quark condensates under the chiral symmetry group and the relation to order parameters of spontaneous chiral symmetry breaking are outlined. In this respect, also the QCD condensates appearing in differences of sum rules of chiral partners are investigated. Finally, the effects of an ambient nuclear medium on the D meson are discussed and relevant condensates are identified. (orig.)
Search for exotic mesons and study of rare mesonic radiative decays at lepton spectrometer
Results of experiments carried out using the ''Lepton-F'' spectrometer, are presented. A new C(1480)-meson with quantum numbers IJPC = 11--, which is a candidate to exotic states, as well as a rare radiation decay D(1285) → Φγ, are detected
Chiral Quark-Meson model of N and DELTA with vector mesons
Vector mesons rho, A1 and ω are introduced in the Chiral Quark-Meson Theory (CQMT) of N and Δ. We propose a new viewpoint for developing CQMT from QCD at the mean-field level. The SU(2) x SU(2) chiral Lagrangian incorporates universal coupling. Accordingly, rho is coupled to the conserved isospin current, A to the partially conserved axial-vector current (PCAC), and ω to the conserved baryon current. As a result the only parameter of the model not directly related to experiment is the quark-pion coupling constant. A fully self-consistent mean-field solution to the model is found for fields in the hedgehog ansatz. The vector mesons play a very important role in the system. They contribute significantly to the values of observables and produce a high-quality fit to many data. The classical stability of the system with respect to hedgehog excitations is analyzed through the use of the Quark-Meson RPA equations (QMRPA)
In-medium QCD sum rules for ω meson, nucleon and D meson
The modifications of hadronic properties caused by an ambient nuclear medium are investigated within the scope of QCD sum rules. This is exemplified for the cases of the ω meson, the nucleon and the D meson. By virtue of the sum rules, integrated spectral densities of these hadrons are linked to properties of the QCD ground state, quantified in condensates. For the cases of the ω meson and the nucleon it is discussed how the sum rules allow a restriction of the parameter range of poorly known four-quark condensates by a comparison of experimental and theoretical knowledge. The catalog of independent four-quark condensates is covered and relations among these condensates are revealed. The behavior of four-quark condensates under the chiral symmetry group and the relation to order parameters of spontaneous chiral symmetry breaking are outlined. In this respect, also the QCD condensates appearing in differences of sum rules of chiral partners are investigated. Finally, the effects of an ambient nuclear medium on the D meson are discussed and relevant condensates are identified. (orig.)
Mesonic and isobar modes in matter
Experiments with heavy ion collisions, like the ones performed at the GSI, are a tool to gain insight in the structure of matter. One key point needed to understand the experimental data is the theoretical description of the in medium properties of mesons and baryons. In this thesis we first developed a self-consistent description for the light vector mesons, ρ and ω, and the pion at finite temperature and in a baryon free environment. A generalisation of these calculations towards finite densities mandatorily needs a reliable description for the pion and the Δ(1232) resonance. Here we extended the approaches discussed in literature by the inclusion of vertex corrections and a selfconsistent and completely relativistic description. Within these models we were able to show that even at high temperatures the ρ-meson properties are not changed dramatically when temperature effects are considered only. In contrast to this the behaviour of the pion and the Δ-isobar is dramatically changed a finite density. The isobar mass-shift is given by an appropriate choice of the mean-fields. Therefore we can not draw a final conclusion about such shifts within our model. In order to do so more calculations, especially of the photo absorption on the nucleus, have to be performed. A further aspect of the calculations presented is that due to a consistent consideration of vertex corrections we were able to achieve a description of the Δ-resonance without the usually used soft formfactor. This is especially important for the in-medium calculations because only in this way we can guarantee that soft modes of the spectrum are treated consistently. The techniques developed within this thesis allow for a straight forward generalisation of the presented models with respect to the consideration of more resonances or couplings. Doing so the here obtained description of the in-medium properties of the considered particles can be refined. (orig.)
Mesonic and isobar modes in matter
Riek, Felix C.
2007-07-01
Experiments with heavy ion collisions, like the ones performed at the GSI, are a tool to gain insight in the structure of matter. One key point needed to understand the experimental data is the theoretical description of the in medium properties of mesons and baryons. In this thesis we first developed a self-consistent description for the light vector mesons, {rho} and {omega}, and the pion at finite temperature and in a baryon free environment. A generalisation of these calculations towards finite densities mandatorily needs a reliable description for the pion and the {delta}(1232) resonance. Here we extended the approaches discussed in literature by the inclusion of vertex corrections and a selfconsistent and completely relativistic description. Within these models we were able to show that even at high temperatures the {rho}-meson properties are not changed dramatically when temperature effects are considered only. In contrast to this the behaviour of the pion and the {delta}-isobar is dramatically changed a finite density. The isobar mass-shift is given by an appropriate choice of the mean-fields. Therefore we can not draw a final conclusion about such shifts within our model. In order to do so more calculations, especially of the photo absorption on the nucleus, have to be performed. A further aspect of the calculations presented is that due to a consistent consideration of vertex corrections we were able to achieve a description of the {delta}-resonance without the usually used soft formfactor. This is especially important for the in-medium calculations because only in this way we can guarantee that soft modes of the spectrum are treated consistently. The techniques developed within this thesis allow for a straight forward generalisation of the presented models with respect to the consideration of more resonances or couplings. Doing so the here obtained description of the in-medium properties of the considered particles can be refined. (orig.)
Semileptonic Ds+(1968) decays as a scalar meson probe
The unusual multiplet structures associated with the light spin zero mesons have recently attracted a good deal of theoretical attention. Here we discuss some aspects associated with the possibility of getting new experimental information on this topic from semileptonic decays of heavy charged mesons into an isosinglet scalar or pseudoscalar plus leptons.
Exotic states of matter in heavy meson decays
Rosner, Jonathan L.
2003-01-01
The potential of decays of mesons containing heavy quarks [including $B$ mesons and the $\\Upsilon(1S)$] for producing final states of matter with unusual quark configurations, such as $q q \\bar q \\bar q$ or $q q q q \\bar q$, is investigated. The usefulness of antineutron detection in such searches is stressed.
Beauty vector meson decay constants from QCD sum rules
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity
Determining the quantum numbers of excited heavy mesons
Eilam, Gad; Krauss, Frank
2000-01-01
We discuss the decays X^* -> Xe^+e^- (``Dalitz decays'') of excited heavy mesons into their ground states and an electron-positron pair. We argue that the measurement of the invariant mass spectrum of the lepton pair gives clear indication on the quantum numbers of the excited meson and thus provides an experimental test of the quark model predictions.
Beauty Vector Meson Decay Constants from QCD Sum Rules
Lucha, Wolfgang; Simula, Silvano
2016-01-01
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
Beauty vector meson decay constants from QCD sum rules
Lucha, Wolfgang; Melikhov, Dmitri; Simula, Silvano
2016-01-01
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
Beauty vector meson decay constants from QCD sum rules
Lucha, Wolfgang [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); Melikhov, Dmitri [Institute for High Energy Physics, Austrian Academy of Sciences, Nikolsdorfergasse 18, A-1050 Vienna (Austria); D. V. Skobeltsyn Institute of Nuclear Physics, M. V. Lomonosov Moscow State University, 119991, Moscow (Russian Federation); Simula, Silvano [Istituto Nazionale di Fisica Nucleare, Sezione di Roma Tre, Via della Vasca Navale 84, I-00146, Roma (Italy)
2016-01-22
We present the outcomes of a very recent investigation of the decay constants of nonstrange and strange heavy-light beauty vector mesons, with special emphasis on the ratio of any such decay constant to the decay constant of the corresponding pseudoscalar meson, by means of Borel-transformed QCD sum rules. Our results suggest that both these ratios are below unity.
First measurement of the B S meson mass
Buskulic, D.; De Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Delfino, M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Mattison, T.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Natali, S.; Nuzzo, S.; Quattromini, M.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Blucher, E.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Hagelberg, R.; Harvey, J.; Haywood, S.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Lohse, T.; Maggi, M.; Markou, C.; Martinez, M.; Mato, P.; Meinhard, H.; Minten, A.; Miotto, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Pusztaszeri, J.-F.; Ranjard, F.; Redlinger, G.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Veenhof, R.; Wachsmuth, H.; Wiedenmann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Badaud, F.; Bardadin-Otwinowska, M.; El Fellous, R.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Prulhière, F.; Saadi, F.; Fearnley, T.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Fouque, G.; Orteu, S.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Georgiopoulos, C.; Ikeda, M.; Lannutti, J.; Levinthal, D.; Sawyer, L.; Wasserbaech, S.; Antonelli, A.; Baldini, R.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; D'Ettorre-Piazzoli, B.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Passalacqua, L.; Pepe-Altarelli, M.; Picchi, P.; Colrain, P.; ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Hanke, P.; Hepp, V.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, R.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Greene, A. M.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Tomalin, I. R.; Wright, A. G.; Girtler, P.; Kneringer, E.; Kuhn, D.; Rudolph, G.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttall, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Steeg, F.; Walther, S. M.; Wanke, R.; Wolf, B.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Carr, J.; Coyle, P.; Drinkard, J.; Etienne, F.; Nicod, D.; Papalexiou, S.; Payre, P.; Roos, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jacobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, W.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, U.; Stiegler, U.; St. Denis, R.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Jaffe, D. E.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Zhang, Z.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Lusiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Carter, J. M.; Gao, Y.; Green, M. G.; March, P. V.; Mir, Ll. M.; Medcalf, T.; Quazi, I. S.; Strong, J. A.; West, L. R.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Ashman, J. G.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Gobbo, B.; Ragusa, F.; Bellantoni, L.; Chen, W.; Cinabro, D.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; LeClaire, B. W.; Lishka, C.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Sharma, V.; Shi, Z. H.; Walsh, A. M.; Weber, F. V.; Wu, Sau Lan; Wu, X.; Zheng, M.; Zobernig, G.
1993-07-01
In a sample of about 1.1 million hadronic Z decays recorded with the ALEPH detector during the 1990-1992 running of LEP, two unambiguous B S meson candidates were observed. From these events the mass of the B S meson has been measured to be 5.3686 ± 0.0056 (stat.) ± 0.0015 (syst.) GeV.
Strange and charm meson masses from twisted mass lattice QCD
We present results of a twisted mass lattice QCD computation of the strange and charm meson spectrum with 2+1+1 dynamical quark flavors. Particular focus is put on excited D and Ds mesons and on a connection to the ''1/2,3/2 limit'' for the D(s)**.
Recent trends in the mesonic description of nuclei
A survey is given of some recent developments in the domain of meson induced phenomena in nuclei. The manifestations of mesonic degrees of freedom are considered in the context of exchange currents as well as that of effective interactions. The significance of past successes is reexamined in the light of recent progress towards a QCD based nuclear theory
Bc-meson production in hadron-hadron collisions
The Bc-meson production cross section was calculated in the perturbative QCD. Various distributions of the charged leptons from the Bc → lνJ/ψ(→l+l-) decay were obtained. The Bc-meson mass measurement from such decays is also discussed. 17 refs., 9 figs., 1 tab
Hydrogen like classification for light nonstrange mesons
Afonin, S. S.
2007-01-01
The recent experimental results on the spectrum of highly excited light nonstrange mesons are known to reveal a high degree of degeneracy among different groups of states. We revise some suggestions about the nature of the phenomenon and put the relevant ideas into the final shape. The full group of approximate mass degeneracies is argued to be $SU(2)_f\\times I\\times O(4)$, where $I$ is the degeneracy of isosinglets and isotriplets and O(4) is the degeneracy group of the relativistic hydrogen...
Two-scale scalar mesons in nuclei
K. Saito; H. Kouno; K. Tsushima; A.W. Thomas
2005-03-01
We generalize the linear sigma model in order to develop a chiral-invariant model of nuclear structure. The model is natural, and contains not only the usual sigma meson which is the chiral partner of the pion but also a new chiral-singlet that is responsible for the medium-range nucleon-nucleon attraction. This approach provides significant advantages in terms of its description of nuclear matter and finite nuclei in comparison with conventional models based on the linear sigma model.
Massive Meson Fluctuation in NJL Model
Huang, Mei(Institute of High Energy Physics, Chinese Academy of Sciences, Beijing, 100049, P.R. China); Zhuang, Pengfei; Chao, Weiqin
1999-01-01
Based on the self-consistent scheme beyond mean-field approximation in the large $N_c$ expansion, including current quark mass explicitly, a general scheme of SU(2) NJL model is developed. To ensure the quark self-energy expanded in the proper order of $N_c$, an approximate internal meson propagator is deduced, which is in order of $O(1/N_c)$. In our scheme, adopting the method of external momentum expansion, all the Feynman diagrams are calculated in a unified way by only expanding the quark...
Meson Mass Decomposition from Lattice QCD
Yang, Yi-Bo; Chen, Ying; Draper, Terrence; Gong, Ming; Liu, Keh-Fei; Liu, Zhaofeng; Ma, Jian-Ping
2014-01-01
Hadron masses can be decomposed as a sum of quark and glue components which are defined through hadronic matrix elements of QCD operators. The components consist of the quark mass term, the quark energy term, the glue energy term, and the trace anomaly term. We calculate these components for mesons with lattice QCD for the first time. The calculation is carried out with overlap fermion on $2+1$ flavor domain-wall fermion gauge configurations. We confirm that $\\sim 50\\%$ of the light pion mass...
Nonleptonic weak decays of charmed mesons
Buccella, F.; Lusignoli, M.; Miele, G.; A. Pugliese; Santorelli, P.
1994-01-01
A previous analysis of two-body Cabibbo allowed nonleptonic decays of $D^0$ mesons and of Cabibbo allowed and first-forbidden decays of $D^+$ and $D_s^+$ has been adjourned using more recent experimental data and extended to the Cabibbo forbidden decays of $D^0$. Annihilation and W-exchange contributions as well as final state interaction effects (assumed to be dominated by nearby resonances) have been included and are in fact crucial to obtain a reasonable agreement with the experimental dat...
Meson Photoproduction Experiments at ELPH, Tohoku University
Ishikawa, Takatsugu; Fujimura, Hisako; Fukasawa, Hiroshi; Hashimoto, Ryo; He, Qinghua; Honda, Yuki; Iwata, Takahiro; Kaida, Shun; Kasagi, Jirohta; Kawano, Atsushi; Kuwasaki, Shuzo; Maeda, Kazushige; Masumoto, Shin'ichi; Miyabe, Manabu; Miyahara, Fusashi; Mochizuki, Kei'ichi; Muramatsu, Norihito; Nakamura, Akihiko; Nawa, Ken'ichi; Ogushi, Shoei; Okada, Yasuyuki; Onodera, Yoshihito; Ozawa, Kyoichiro; Sakamoto, Yasunobu; Sato, Mamoru; Shimizu, Hajime; Sugai, Hiroyuki; Suzuki, Koutaku; Tajima, Yasuhisa; Takahashi, Shin'ichiro; Taniguchi, Yusuke; Tsuchikawa, Yusuke; Yamazaki, Hirohito; Yamazaki, Ryuji; Yoshida, Hiroshi Y.
Meson photoproduction experiments have been conducted with an electromagnetic (EM) calorimeter FOREST at Research Center for Electron Photon Science (ELPH), Tohoku University. A narrow resonance observed at W = 1670 MeV in η photoproduction on the neutron is of great interest, which is a candidate of an anti-decuplet pentaquark baryon although its origin is still controversial. The preliminary results of the cross sections for π0 and η photoproduction on the deuteron are presented. The next generation FOREST experiments have been planned to study S11(1535) properties in the nuclear medium by searching for η-mesic nucleus states. The planned experiments are also shown in this contribution.
Status of Meson Photoproduction Experiments with CLAS
Pasyuk, Eugene A.
2014-01-01
A large part of the experimental program in Hall B of the Jefferson Lab is dedicated to baryon spectroscopy. Meson photoproduction experiments are essential part of this program. CEBAF Large Acceptance Spectrometer (CLAS) and availability of circularly and linearly polarized tagged photon beams in combination with longitudinally and transversely polarized frozen spin targets provide unique conditions for this type of experiments. For the first time, a complete or nearly complete measurement became possible and will allow model independent extraction of the reaction amplitude. The measurements were complete with both proton and deuteron targets. An overview of the collected experimental data will be presented.
Spectroscopic properties of the B meson
Devlani Nayneshkumar
2015-01-01
Full Text Available Investigation of the B(bq̄; q = u, d meson properties is carried out using variational method within phenomenological quark antiquark potential(coulomb plus power model using the Gaussian wave function. O(1/m correction to the potential energy term and relativistic corrections to the kinetic energy term of the hamiltonian are incorporated. Spin-orbit, spin-spin and tensor interactions are employed to obtain the mass spectra. Various other properties such as the decay constants, e1 and m1 transitions are also obtained
Theoretical aspects of light meson spectroscopy
Barnes, T. [Oak Ridge National Lab., TN (United States). Computational and Theoretical Physics Group]|[Univ. of Tennessee, Knoxville, TN (United States). Dept. of Physics and Astronomy
1995-12-31
In this pedagogical review the authors discuss the theoretical understanding of light hadron spectroscopy in terms of QCD and the quark model. They begin with a summary of the known and surmised properties of QCD and confinement. Following this they review the nonrelativistic quark potential model for q{anti q} mesons and discuss the quarkonium spectrum and methods for identifying q{anti q} states. Finally, they review theoretical expectations for non-q{anti q} states (glueballs, hybrids and multiquark systems) and the status of experimental candidates for these states.
Weak decays of strongly decaying mesons
Weak decays of the light mesons η, η', ρ, ω and κ* are considered. It is pointed out that a measurement of the decays η' → κπ, ρ → π, ω → κπ and κ* → ππ is within reach at LEAR. This would give valuable information on the mechanism behind the ΔI = 1/2 rule in weak nonleptonic decays. A possible strangeness asymmetry in these decays is proposed as a manifestation of CP violation. However, this asymmetry is estimated in the standard electroweak model to be too minute to be measurable at present. (orig.)
Neutral meson oscillations on the lattice
Carrasco, Nuria
2014-01-01
Accurate measurements of K, D and B meson mixing amplitudes provide stringent constraints in the Unitary Triangle analysis, as well as useful bounds on New Physics scales. Lattice QCD provides a non perturbative tool to compute the hadronic matrix elements entering in the effective weak Hamiltonian, with errors at a few percent level and systematic uncertainties under control. I review recent lattice results for these hadronic matrix element performed with $N_f=2$, $N_f=2+1$ and $N_f=2+1+1$ dynamical sea quarks.
Charmed Mesons in Nuclei with Heavy-Quark Spin Symmetry
Tolos, L.; Garcia-Recio, C.; Nieves, J.; Romanets, O.; Salcedo, L. L.
2013-08-01
We study the properties of charmed pseudoscalar and vector mesons in dense matter within a unitary meson-baryon coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa Lagrangian to incorporate spin-flavor symmetry and implement a suitable flavor symmetry breaking. Several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with 1/2+ and 3/2+ baryons. Those states are then compared to experimental data as well as theoretical models. Next, Pauli-blocking effects and meson self-energies are introduced in a self-consistent manner to obtain the open-charm meson spectral functions in a dense nuclear environment. We finally discuss the formation of D-mesic nuclei.
Charmed mesons in nuclei with heavy-quark spin symmetry
Tolos, L; Nieves, J; Romanets, O; Salcedo, L L
2012-01-01
We study the properties of charmed pseudoscalar and vector mesons in dense matter within a unitary meson-baryon coupled-channel model which incorporates heavy-quark spin symmetry. This is accomplished by extending the SU(3) Weinberg-Tomozawa Lagrangian to SU(8) spin-flavor symmetry and implementing a suitable flavor symmetry breaking. Several resonances with negative parity are generated dynamically by the s-wave interaction between pseudoscalar and vector meson multiplets with $1/2^+$ and $3/2^+$ baryons. Those states are then compared to experimental data as well as theoretical models. Next, Pauli-blocking effects and meson self-energies are introduced in a self-consistent manner to obtain the open-charm meson spectral functions in a dense nuclear environment. We finally discuss the formation of $D$-mesic nuclei.
Hyperfine meson splittings: chiral symmetry versus transverse gluon exchange
Llanes-Estrada, Felipe J; Swanson, Eric S; Szczepaniak, Adam P; Llanes-Estrada, Felipe J.; Cotanch, Stephen R.; Szczepaniak, Adam P.; Swanson, Eric S.
2004-01-01
Meson spin splittings are examined within an effective Coulomb gauge QCD Hamiltonian incorporating chiral symmetry and a transverse hyperfine interaction necessary for heavy quarks. For light and heavy quarkonium systems the pseudoscalar-vector meson spectrum is generated by approximate BCS-RPA diagonalizations. This relativistic formulation includes both $S$ and $D$ waves for the vector mesons which generates a set of coupled integral equations. A smooth transition from the heavy to the light quark regime is found with chiral symmetry dominating the $\\pi$-$\\rho$ mass difference. A good, consistent description of the observed meson spin splittings and chiral quantities, such as the quark condensate and the $\\pi$ mass, is obtained. Similar comparisons with TDA diagonalizations, which violate chiral symmetry, are deficient for light pseudoscalar mesons indicating the need to simultaneously include both chiral symmetry and a hyperfine interaction. The $\\eta_b$ mass is predicted to be around 9400 MeV consistent w...
Meson turbulence at quark deconfinement from AdS/CFT
Hashimoto, Koji; Murata, Keiju; Oka, Takashi
2014-01-01
Based on the QCD string picture at confining phase, we conjecture that the deconfinement transition always accompanies a condensation of higher meson resonances with a power-law behavior, "meson turbulence". We employ the AdS/CFT correspondence to calculate the meson turbulence for $\\mathcal{N}=2$ supersymmetric QCD at large $N_c$ and at strong coupling limit, and find that the energy distribution to each meson level $n$ scales as $n^\\alpha$ with the universal scaling $\\alpha=-5$. The universality is checked for various ways to attain the quark deconfinement: a static electric field below/around the critical value, a time-dependent electric field quench, and a time-dependent quark mass quench, all result in the turbulent meson condensation with the universal power $\\alpha=-5$ around the deconfinement.
Probing the perturbative dynamics of exclusive meson pair production
Harland-Lang, L.A., E-mail: lucian.harland-lang@durham.ac.uk [Department of Physics and Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE (United Kingdom); Khoze, V.A. [Department of Physics and Institute for Particle Physics Phenomenology, University of Durham, DH1 3LE (United Kingdom); Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, St. Petersburg, 188300 (Russian Federation); Ryskin, M.G. [Petersburg Nuclear Physics Institute, NRC Kurchatov Institute, Gatchina, St. Petersburg, 188300 (Russian Federation); Stirling, W.J. [Cavendish Laboratory, University of Cambridge, J.J. Thomson Avenue, Cambridge, CB3 0HE (United Kingdom)
2013-10-01
We present the results of a recent novel application of the ‘hard exclusive’ perturbative formalism to the process gg→MM{sup ¯} at large angles, where M (M{sup ¯}) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg→qq{sup ¯}(gg)qq{sup ¯}(gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k{sub ⊥}, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the η{sup ′} and η mesons display significant sensitivity to any valence gg component of the meson wavefunctions.
Probing the perturbative dynamics of exclusive meson pair production
Harland-Lang, L A; Ryskin, M G; Stirling, W J
2013-01-01
We present the results of a recent novel application of the `hard exclusive' perturbative formalism to the process gg --> MMbar at large angles, where M (Mbar) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg --> qqbar(gg) qqbar(gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k_t, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the eta' and eta mesons display significant sensitivity to any valence gg component of the meson wavefunctions.
Probing the perturbative dynamics of exclusive meson pair production
Harland-Lang, L. A.; Khoze, V. A.; Ryskin, M. G.; Stirling, W. J.
2013-10-01
We present the results of a recent novel application of the 'hard exclusive' perturbative formalism to the process gg → MMbar at large angles, where M (Mbar) is a light meson (anti-meson). As well as discussing the important theoretical features of the relevant leading-order gg → qqbar (gg) qqbar (gg) 6-parton amplitudes, we also comment on their phenomenological implications. In particular, we consider the central exclusive production of meson pairs at comparatively large transverse momentum k⊥, which is expected to proceed via this mechanism. We show that this leads to various non-trivial predictions for a range of exclusive processes, and that the cross sections for the η‧ and η mesons display significant sensitivity to any valence gg component of the meson wavefunctions.
Valid QCD sum rules for vector mesons in nuclear matter
QCD sum rules for vector mesons (ρ, ω, φ) in nuclear matter are re-examined with an emphasis on the reliability of various sum rules. Monitoring the continuum contribution and the convergence of the operator product expansion plays crucial role in determining the validity of a sum rule. The uncertainties arising from less than precise knowledge of the condensate values and other input parameters are analyzed via a Monte Carlo error analysis. Our analysis leaves no doubt that vector-meson masses decrease with increasing density. This resolves the current debate over the behavior of the vector-meson masses and the sum rules to be used in extracting vector meson properties in nuclear matter. We find a ratio of ρ-meson masses of mρ*/mρ = 0.78 ± 0.08 at nuclear matter saturation density. (author). 37 refs., 6 figs
Quantum chromodynamics with infinite number of vector mesons
It is supposed that families of vector mesons ρ, ψ, Υ contain an infinite number of resonances with gradually increasing widths. The asymptotic freedom requirement involves a relationship between the electronic width of a resonance and its mass derivative over the number. Using of this relationship it is shown that for the families of ψ and Υ mesons the moment from experimental function R(s)is egual to the sum of the moment from a bare quark loop and the edge term which arised from replacing of summation by integration. These equalities are fulfilled up to 1% for 60 moments in the ψ-meson family and up to 2% for 96 moments in the Υ-meson family. The electronic widths of the considered resonances and the ρ-meson mass are calculated
Factorization for hard exclusive electroproduction of mesons in QCD
We formulate and prove a QCD factorization theorem for hard exclusive electroproduction of mesons in QCD. The proof is valid for the leading power in Q and all logarithms. This generalizes previous work on vector meson production in the diffractive region of small x. The amplitude is expressed in terms of off-diagonal generalizations of the usual parton densities. The full theorem applies to all kinds of mesons and not just to vector mesons. The parton densities used include not only the ordinary parton density, but also the helicity density (g1 or Δq) and the transversity density (h1 or δq), and these can be probed by measuring the polarization of the produced mesons with unpolarized protons. copyright 1997 The American Physical Society
Rapidity resummation for $B$-meson wave functions
Shen, Yue-Long
2014-01-01
Transverse-momentum dependent (TMD) hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity $\\zeta$ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for $B$-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic $B$-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of $B$-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive $B$-meson decays. The phenomenological consequence of rapidity-resummation improved $B$-meson wave functions is further discussed in the context of $B \\t...
Photoproduction of $\\eta '$-mesons off the deuteron
Jaegle, I; Fix, A; Huang, F; Nakayama, K; Tiator, L; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D E; Beck, R; Beloglazov, Y A; Castelijns, R; Crede, V; Dutz, H; Elsner, D; Ewald, R; Frommberger, F; Funke, C; Gregor, R; Gridnev, A B; Gutz, E; Hillert, W; Hoeffgen, S; Junkersfeld, J; Kalinowsky, H; Kammer, S; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Kotulla, M; Krusche, B; Lang, M; Loehner, H; Lopatin, I V; Lugert, S; Menze, D; Messchendorp, J G; Metag, V; Nikonov, V A; Nanova, M; Novinski, D V; Novotny, R; Ostrick, M; Pant, L M; van Pee, H; Pfeiffer, M; Roy, A; Sarantsev, A V; Schadmand, S; Schmidt, C; Schmieden, H; Schoch, B; Shende, S V; Sokhoyan, V; Suele, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Wendel, C
2010-01-01
Quasi-free photoproduction of $\\eta '$ mesons off nucleons bound in the deuteron has been measured with the combined Crystal Barrel - TAPS detector. The experiment was done at a tagged photon beam of the ELSA electron accelerator in Bonn for incident photon energies from the production threshold up to 2.5 GeV. The $\\eta '$-mesons have been detected in coincidence with recoil protons and recoil neutrons. The quasi-free proton data are in good agreement with the results for free protons, indicating that nuclear effects have no significant impact. The coincidence with recoil neutrons provides the first data for the $\\gamma n \\rightarrow n\\eta '$ reaction. In addition, also first estimates for coherent $\\eta '$-production off the deuteron have been obtained. In agreement with model predictions, the total cross section for this channel is found to be very small, at most at the level of a few nb. The data are compared to model calculations taking into account contributions from nucleon resonances and $t$-channel ex...
High-energy photoproduction of neutral mesons
Charity, Tim
1987-01-01
This thesis presents results from the first full period of data-taking of the experiment WA69 at the Omega^'^ectrometer, CERN, Geneva. The experiment used a tagged photon beam of energy 60-180 GeV incident on a liquid hydrogen target to study photoproduction of hadronic states. The various components of the experiment are described, with particular emphasis on the electromagnetic calorimeters, and the associated offline software for event reconstruction and acceptance calculation. The performance of the outer calorimeter is discussed, and the pi^0 detection and reconstruction efficiency is examined by comparison with pi^{+/- } production. Searches for photoproduction of neutral meson states reveal a clear signal for the pi^0, eta^0 , and omega^0 mesons. The cross-section for elastic omega^0 production is estimated, and found to be consistent with the established value of 1 mub. The cross-section for inclusive pi^0 and eta^0 production is studied using the variable Feynman-x (x_{F }), and pi^0 production as a ...
Asymmetric vector mesons produced in nuclear collisions
Dremin, I M
2016-01-01
It is argued that the experimentally observed phenomenon of asymmetric shapes of vector mesons produced in nuclear media during high energy nucleus-nucleus collisions can be explained as Fano-Feshbach resonances. It has been observed that the mass distributions of lepton pairs created at meson decays decline from the traditional Breit-Wigner shape with some excess in the low-mass wing of the resonance. It is clear that the whole phenomenon is related to some interaction with the nuclear medium. Moreover, it can be further detalized in quantum mechanics as the interference of direct and continuum states in Fano-Feshbach effect. To reveal the nature of the interaction it is proposed to use a phenomenological model of the additional contribution due to Cherenkov gluons. They can be created because of the excess of the refractivity index over 1 just in the low-mass wing as required by the classical Cherenkov treatment. In quantum mechanics, this requirement is related to the positive real part of the interaction ...
Beautiful mesons from QCD spectral sum rules
Narison, S.
1988-08-18
We apply q/sup 2/ = 0 moments within n (number of derivatives) and t/sub c/ (continuum threshold) stability criteria to the beautiful-meson systems. The optimal predictions are reached for the same ranges of n and t/sub c/ values leading to the previous estimate of the decay constant f/sub B/. The QCD scales (b-quark 'physical' mass, mixed and four-quark condensates) are strongly constrained by the observed B and B/sup */ masses. The predictions for the S- and P-state splittings are much affected by the definition of the b-quark mass (pole or euclidian) entering into the Wilson coefficients of the non-perturbative condensates. The size of the SU(3)/sub F/ breaking on the mass splittings cannot be accurately predicted due to the imprecise value of the
Constraining New Physics with D meson decays
Latest Lattice results on D form factors evaluation from first principles show that the Standard Model (SM) branching ratios prediction for the leptonic Ds→ℓνℓ decays and the semileptonic SM branching ratios of the D0 and D+ meson decays are in good agreement with the world average experimental measurements. It is possible to disprove New Physics hypothesis or find bounds over several models beyond the SM. Using the observed leptonic and semileptonic branching ratios for the D meson decays, we performed a combined analysis to constrain non-standard interactions which mediate the cs¯→lν¯ transition. This is done either by a model-independent way through the corresponding Wilson coefficients or in a model-dependent way by finding the respective bounds over the relevant parameters for some models beyond the Standard Model. In particular, we obtain bounds for the Two Higgs Doublet Model Type-II and Type III, the Left–Right model, the Minimal Supersymmetric Standard Model with explicit R-parity violation and Leptoquarks. Finally, we estimate the transverse polarization of the lepton in the D0 decay and we found it can be as high as PT=0.23.
This report summarises the results of the physics programme, performed in the years 1998-2003, which became possible after taking into operation the ANKE spectrometer at an internal target position of the accelerator facility COSY-Juelich. Primary goal when building ANKE was to provide a tool which allows one to study processes leading to K+-meson production in interactions of protons with atomic nuclei, in particular at beam energies far below the free nucleon-nucleon threshold. From such data one hopes to extract information about the influence of the nuclear medium on elementary K+-production processes (i.e. in free proton-proton interactions), about the in-medium properties of this meson, and about collective effects in nuclear matter. The construction of ANKE and the K+-detection systems was started in 1989. After the integration of ANKE into the COSY accelerator ring in 1998, inclusive K+-momentum spectra were measured in a first series of experiments (p+A → K+X for different target nuclei A=C, Cu, Ag, Au). These data reveal a high degree of collectivity in the target nuclei and, for the first time, allow one to extract the nuclear potential (or ''in-medium mass'') of K+ mesons at normal nuclear density with high accuracy. The ANKE data on K+ production in proton-deuteron interactions indicate a large production cross section on neutrons, as compared to proton targets. This fact must be taken into account, e.g., for the theoretical description of heavy ion data. In the second phase of the experimental program, K+ mesons from protoncarbon interactions were measured in coincidence with protons and deuterons (p+C → K+ (p or d)X). These novel data yield information about the kaon production mechanisms and give evidence for cluster-formation processes. Corresponding coincidence data for proton-proton collisions (p+p → K+ anti K0 d) revealed that K anti K -pair production close to threshold is dominated by kaons produced in a relative S-wave. This has been
Takahashi, Y.; Eby, P. B.
1985-01-01
Possibilities of observing abundances of phi mesons and narrow hadronic pairs, as results of QGP and Chiral transitions, are considered for nucleus-nucleus interactions. Kinematical requirements in forming close pairs are satisfied in K+K decays of S(975) and delta (980) mesons with small phi, and phi (91020) mesons with large PT, and in pi-pi decays of familiar resonance mesons only in a partially restored chiral symmetry. Gluon-gluon dominance in QGP can enhance phi meson production. High hadronization rates of primordial resonance mesons which form narrow hadronic pairs are not implausible. Past cosmic ray evidences of anomalous phi production and narrow pair abundances are considered.
On Decays of B Mesons to a Strange Meson and an η or η' Meson at Babar
We describe studies of the decays of B mesons to final states ηK*(892), ηK*0(S-wave), ηK*2(1430), and η'K based on data collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collier at the Stanford Linear Accelerator Center. We measure branching fractions and charge asymmetries for the decays B → ηK*, where K* indicates a spin 0, 1, or 2 Kπ system, making first observations of decays to final states ηK*00(S-wave), ηK*+0 (S-wave), and ηK*02(1430). We measure the time-dependent CP-violation parameters S and C for the decays B0 → η'K0, observing CP violation in a charmless B decay with 5σ significance considering both statistical and systematic uncertainties..
Investigation of Semileptonic B Meson Decays to p -Wave Charm Mesons
We have studied semileptonic B meson decays with a p -wave charm meson in the final state using 3.29x106 BB events collected with the CLEOII detector at the Cornell Electron-Positron Storage Ring. We find a value for the exclusive semileptonic product branching fraction B(B-→D01 ell -νell) B(D01→D*+ π-)=(0.373±0.085± 0.052±0.024)% and an upper limit for B(B-→D*02 ell -νell) B(D*02→D*+ π-)2 spectrum for B-→D01 ell - νell . copyright 1998 The American Physical Society
Interaction of eta mesons with nuclei
Kelkar, N. G.; Khemchandani, K. P.; Upadhyay, N. J.; Jain, B. K.
2013-06-01
Back in the mid-1980s, a new branch of investigation related to the interaction of eta mesons with nuclei came into existence. It started with the theoretical prediction of possible exotic states of eta mesons and nuclei bound by the strong interaction and later developed into an extensive experimental program to search for such unstable states as well as understand the underlying interaction via eta-meson producing reactions. The vast literature of experimental as well as theoretical works that studied various aspects of eta-producing reactions such as the π+n → ηp, pd → 3Heη, p 6Li → 7Be η and γ 3He → η X, to name a few, had but one objective in mind: to understand the eta-nucleon (ηN) and hence the η-nucleus interaction which could explain the production data and confirm the existence of some η-mesic nuclei. In spite of these efforts, there remain uncertainties in the knowledge of the ηN and hence the η-nucleus interaction. Therefore, this review is an attempt to bind together the findings in these works and draw some global and specific conclusions which can be useful for future explorations. The ηN scattering length (which represents the strength of the η-nucleon interaction) using different theoretical models and analyzing the data on η production in pion, photon and proton induced reactions was found to be spread out in a wide range, namely, 0.18 ⩽ ℜe aηN ⩽ 1.03 fm and 0.16 ⩽ ℑm aηN ⩽ 0.49 fm. Theoretical searches of heavy η-mesic nuclei based on η-nucleus optical potentials and lighter ones based on Faddeev type few-body approaches predict the existence of several quasibound and resonant states. Although some hints of η-mesic states such as ^3_{\\eta} He and ^{25}_{\\eta} Mg do exist from previous experiments, the promise of clearer signals for the existence of η-mesic nuclei lies in the experiments to be performed at the J-PARC, MAMI and COSY facilities in the near future. This review is aimed at giving an overall
A calculation of the physical mass of sigma meson
J R Morones-Ibarra; Ayax Santos-Guevara
2007-06-01
We calculate the physical mass and the width of the sigma meson by considering that it couples in vacuum to two virtual pions. The mass is calculated by using the spectral function, and we find that it is about 600 MeV. In addition, we obtained 220 MeV as the value for the width of its spectral function. The value obtained for the mass is in good agreement with that reported in the Particle Data Book for the σ-meson, which is also named 0(600). This result also shows that -meson can be considered as a two-pion resonance.
The {eta}' meson from lattice QCD
Jansen, K. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Michael, C. [Liverpool Univ. (United Kingdom). Theoretical Physics Div.; Urbach, C. [Humboldt Univ. Berlin (Germany). Inst. fuer Elementarteilchenphysik
2008-04-15
We study the flavour singlet pseudoscalar mesons from first principles using lattice QCD. With N{sub f}=2 flavours of light quark, this is the so-called {eta}{sub 2} meson and we discuss the phenomenological status of this. Using maximally twisted-mass lattice QCD, we extract the mass of the {eta}{sub 2} meson at two values of the lattice spacing for lighter quarks than previously discussed in the literature. We are able to estimate the mass value in the limit of light quarks with their physical masses. (orig.)
K meson leptonic decays progress in nuclear physics
Bailey, J; Jones, P B; Brink, D M; Mulvey, J H
2013-01-01
Progress in Nuclear Physics, Volume 12, Part 1: K Meson Leptonic Decay: The Anomalous Magnetic Moment of the Muon and Related Topics focuses on K Meson leptonic decay. The volume first discusses K Meson leptonic decay, including weak hadronic current, polarization of the muon, form of coupling, rate of partial decay, and density function of the Dalitz plot. The text then takes a look at the anomalous magnetic moment of the muon and other topics. The theory of the anomalous magnetic moment of electrons and muon and clock paradox, including muon and special relativity and lifetime of the muon in
Latest results from meson photoproduction at ELSA and MAMI
Krusche B.
2014-06-01
Full Text Available Photoproduction of mesons plays a key role for the investigation of the excitation spectrum of the nucleon and thus for our understanding of the strong interaction in the non-perturbative regime. In this contribution we discuss recent results from the experiments at the tagged photon beams of the electron accelerators ELSA in Bonn and MAMI in Mainz. They include the measurement of cross sections and (double polarization observables for single meson production and production of meson pairs off free protons as well as of quasi-free nucleons bound in light nuclei (in particular the deuteron.
Measuring Polarized Gluon and Quark Distributions with Meson Photoproduction
Afanasiev, A M; Wahlquist, C; Afanasev, Andrei; Carlson, Carl E.; Wahlquist, Christian
1998-01-01
We calculate polarization asymmetries in photoproduction of high transverse momentum mesons, focusing on charged pions, considering the direct, fragmentation, and resolved photon processes. The results at very high meson momentum measure the polarized quark distributions and are sensitive to differences among the existing models. The results at moderate meson momentum are sensitive to the polarized gluon distribution and can provide a good way to measure it. Suitable data may come as a by-product of deep inelastic experiments to measure $g_1$ or from dedicated experiments.
Calculation of the D and B meson lifetimes
Using the expansions of the heavy meson decay widths in the heavy quark mass and QCD sum rules for estimates of corresponding matrix elements the D±,O,S decay widths and the B±,O,S lifetime differences are calculated. The results for D mesons are in agreement with the data, while it is predicted that [Γ(BO)-Γ(B-)]/ΓB≅4%, and the lifetime difference of the BO and BS mesons is even smaller. The role of the weak annihilation and Pauli interference contributions to the lifetime differences are described in detail. 55 refs.; 10 figs
Proposal of the meson theory by Hideki Yukawa
In 1935 Hideki Yukawa courageously proposed a new field theory of the nuclear forces and predicted the existence of the meson, a particle responsible for the strong interaction. This was during a period when new particles were not welcomed in the domain of physics. Later, the meson theory greatly promoted the advancement of nuclear physics. The theory was verified after the π-meson was discovered in cosmic rays by C.P.Powell, a British physicist. Yukawa was awarded the Nobel Prize in 1949 for his contribution to physics
Electroproduction of Roper Resonance in a Meson Cloud Model
CHEN Dian-Yong; DONG Yu-Bing
2008-01-01
The Q2 dependencies of Roper resonance (N* (1440)) helicity amplitudes have been discussed based on two assumptions:(I) the Roper resonance is an excitation of one of the three quarks,and (ii) the quarks are surrounded by a pion-meson cloud.Our study shows that the mixing of the ground state in the Roper wavefunction caused by the pion meson cloud together with the pion meson cloud itself is crucial for the predictions of the photoproduction amplitudes of the Roper resonance.It is found that our model can give a good description for the helicity amplitudes of the Roper resonance comparing with the experimental measurement.
Calculation of the D and B Meson Lifetimes
Chernyak, Victor
1994-01-01
Using the expansions of the heavy meson decay widths in the heavy quark mass and QCD sum rules for estimates of corresponding matrix elements,\\, we calculate the $D^{\\pm,o,s}$ decay widths and the $B^{\\pm,o,s}$ lifetime differences. The results for D mesons are in agreement with the data,\\, while it is predicted that $[\\Gamma (B^o)-\\Gamma (B^-)]/\\Gamma_B\\se 4\\%\\,,$ and the lifetime difference of the $B^o$ and $B_s$ mesons is even smaller. The role of the weak annihilation and Pauli interferen...
Transversity in hard exclusive electroproduction of pseudoscalar mesons
Estimates for electroproduction of pseudoscalar mesons at small values of skewness are presented. Cross-sections and asymmetries for these processes are calculated within the handbag approach which is based on factorization in hard parton subprocesses and soft generalized parton distributions (GPDs). The latter are constructed from double distributions. Transversity GPDs are taken into account; they are accompanied by twist-3 meson wave functions. For most pseudoscalar-meson channels a combination of HT and anti ET plays a particularly prominent role. This combination of GPDs, which we constrain by moments obtained from lattice QCD, leads, with the exception of the π+ and η' channels, to large transverse cross-sections. (orig.)
Measuring polarized gluon and quark distributions with meson photoproduction
The authors calculate polarization asymmetries in photoproduction of high transverse momentum mesons, focusing on charged pions, considering the direct, fragmentation, and resolved photon processes. The results at very high meson momentum measure the polarized quark distributions and are sensitive to differences among the existing models. The results at moderate meson momentum are sensitive to the polarized gluon distribution and can provide a good way to measure it. Suitable data may come as a by-product of deep inelastic experiments to measure g1 or from dedicated experiments
Quantum correlations in B and K meson systems
Banerjee, Subhashish; MacKenzie, Richard
2014-01-01
We study quantum correlations in meson-antimeson systems, as provided for example in meson factories used mainly to probe physics beyond the Standard Model of particle physics. We use a semigroup formalism to compute a trace-preserving density matrix for these systems, in spite of the fact that the particles are unstable. This is used to compute the time evolution of several measures of quantum correlations for three meson systems (KKbar, BdBdbar and BsBsbar). We find that the quantum correlations for these systems can be non-trivially different from their stable counterparts.
Cross sections for inelastic meson-meson scattering via quark-antiquark annihilation
Shen, Zhen-Yu; Xu, Xiao-Ming; Weber, H. J.
2016-08-01
We study inelastic meson-meson scattering that is governed by quark-antiquark annihilation and creation involving a quark and an antiquark annihilating into a gluon, and subsequently the gluon creating another quark-antiquark pair. The resultant hadronic reactions include for I =1 : π π →ρ ρ , K K ¯→K*K¯*, K K¯*→K*K¯*, K*K ¯→K*K¯*, as well as π π →K K ¯, π ρ →K K¯*, π ρ →K*K ¯, and K K ¯→ρ ρ . In each reaction, one or two Feynman diagrams are involved in the Born approximation. We derive formulas for the unpolarized cross section, the transition amplitude, and the transition potential for quark-antiquark annihilation and creation. The unpolarized cross sections for the reactions are calculated at six temperatures, and prominent temperature dependence is found. It is due to differences among mesonic temperature dependence in hadronic matter.
Temperature dependence of cross sections for meson-meson nonresonant reactions in hadronic matter
Shen, Zhen-Yu
2014-01-01
We study unpolarized cross sections for the endothermic nonresonant reactions: pion pion to rho rho for I=2, KK to K*K* for I=1, KK* to K*K* for I=1, pion K to rho K* for I=3/2, pion K* to rho K* for I=3/2, rho K to rho K* for I=3/2, and pion K* to rho K for I=3/2, which take place in hadronic matter. We provide a potential that is given by perturbative QCD with loop corrections at short distances, becomes a distance-independent and temperature-dependent value at long distances, and has a spin-spin interaction with relativistic modifications. The Schrodinger equation with the potential yields temperature-dependent meson masses and mesonic quark-antiquark relative-motion wave functions. In the first Born approximation with the quark-interchange mechanism, the temperature dependence of the potential, meson masses and wave functions brings about temperature dependence of unpolarized cross sections for the seven nonresonant reactions. Noticeably, rapid changes of pion and K radii cause an increase in peak cross s...
From the Deuteron to Deusons, an Analysis of Deuteronlike Meson-Meson Bound States
Törnqvist, N A
1994-01-01
A systematic study of possible deuteronlike two-meson bound states, {\\it deusons}, is presented. Previous arguments that many such bound states may exist are elaborated with detailed arguments and numerical calculations including, in particular, the tensor potential. In the heavy meson sector one-pion exchange alone is strong enough to form at least deuteron-like $B\\bar B^*$ and $B^*\\bar B^*$ composites bound by approximately 50 MeV. Composites of $D\\bar D^*$ and $D^*\\bar D^*$ states bound by pion exchange alone are expected near the thresholds, while in the light meson sector one generally needs some additional short range attraction to form bound states. The quantum numbers of these states are I=0, In $B\\bar B^*$ one predictss the states: $\\eta_b(\\approx 10545),\\ \\chi_{b1}(\\approx 10562)$, and in $B^*\\bar B^*$ one finds the states: $\\eta_b(\\approx 10590),\\ \\chi_{b0}(\\approx 10582),\\ h_b(\\approx 10608),\\ \\chi_{b2}(\\approx 10602)$. Near the $D\\bar D^*$ threshold the states: $\\eta_c(\\approx 3870),\\ \\chi_{c0}(\\...
Observation of charmless B meson decays
Using the ARGUS detector at the e+e- storage ring DORIS II, we have observed charmless decays of B mesons into the final states panti pπ± and panti pπ+π-. The significance of the signal corresponds to more than five standard deviations. The branching ratios are (5.2±1.4±1.9)x10-4 for the three-body and (6.0±2.0±2.2)x10-4 for the four-body final state. These decays cannot proceed via the dominant b→c transitions, and we show that they are not the result of penguin-type processes. Thus, the observed decays must represent b→u quark transitions. Consequently, the Kobayashi-Maskawa matrix element Vub is non-zero. (orig.)
Study of inclusive semileptonic B meson decays
Using the ARGUS detector at the e+e- storage ring DORIS-II, we have measured the inclusive semileptonic decays of B-mesons into electrons and muons. The data originate from 220.5 events/pb on the Υ(4S) resonance. We find BR(B→e+veX)=(10.3±0.6±0.2)% and BR(B→μ+vμX)=(10.0±0.6±0.2)% using the model of Altarelli et al. for extrapolating over all lepton momenta, and BR(B→e+vceX)=(9.9±0.6)%, BR(B→μ+vμX)=(9.7±0.6)% using the model of Grinstein et al. For semileptonic decays into baryons, we obtain an upper limit of BR(B→anti pe+vX)<0.16%(90%CL). (orig.)
Model discrimination in pseudoscalar-meson photoproduction
Nys, J; Ireland, D G; Glazier, D I
2016-01-01
To learn about a physical system of interest, experimental results must be able to discriminate among models. We introduce a geometrical measure to quantify the distance between models for pseudoscalar-meson photoproduction in amplitude space. Experimental observables, with finite accuracy, map to probability distributions in amplitude space, and the characteristic width scale of such distributions needs to be smaller than the distance between models if the observable data are going to be useful. We therefore also introduce a method for evaluating probability distributions in amplitude space that arise as a result of one or more measurements, and show how one can use this to determine what further measurements are going to be necessary to be able to discriminate among models.
Delta, iota and other meson spectroscopies
This talk is given from the point of view of an experimentalist. Meson spectroscopy in the 1 to 3 GeV region is interesting because experiments exploring this region, in particular radiative psi decay, have found a rich structure of resonances too complicated to unravel with any one experiment, and not easily interpreted with any one theoretical model. None of the theoretical calculations predicting all kinds of interesting and exotic objects in this region is very convincing or reliable. Additional input from anti pp annihilation can be very useful in helping to find the answers to the following open questions: what exactly is this spectrum, what are the masses and quantum numbers of the resonances, as determined from analysis of data without theoretical prejudices; how is this spectrum described by QCD, is there evidence for new kinds of states like glue-balls, hybrids, axions, Higgses or multiquark exotics, and is there any evidence for new physics beyond QCD. 20 refs
Nonleptonic weak decays of charmed mesons
Buccella, F.; Lusignoli, M.; Miele, G.; Pugliese, A.; Santorelli, P.
1995-04-01
A previous analysis of two-body Cabibbo-allowed nonleptonic decays of D0 mesons and of Cabibbo-allowed and first-forbidden decays of D+ and D+s has been adjourned using more recent experimental data and extended to the Cabibbo-forbidden decays of D0. Annihilation and W-exchange contributions as well as final state interaction effects (assumed to be dominated by nearby resonances) have been included and are in fact crucial to obtain a reasonable agreement with the experimental data, which show large flavor SU(3) violations. New fitting parameters are necessary to describe rescattering effects for Cabibbo-forbidden D0 decays, given the lack of experimental information on isoscalar resonances. We keep their number to a minimum, three, using phenomenologically based considerations. We also discuss CP-violating asymmetries.
Nonleptonic weak decays of charmed mesons
Buccella, F; Miele, G; Pugliese, A; Santorelli, P; Buccella, F; Lusignoli, M; Miele, G; Pugliese, A; Santorelli, P
1995-01-01
A previous analysis of two-body Cabibbo allowed nonleptonic decays of D^0 mesons and of Cabibbo allowed and first-forbidden decays of D^+ and D_s^+ has been adjourned using more recent experimental data and extended to the Cabibbo forbidden decays of D^0. Annihilation and W-exchange contributions as well as final state interaction effects (assumed to be dominated by nearby resonances) have been included and are in fact crucial to obtain a reasonable agreement with the experimental data, which show large flavour SU(3) violations. New fitting parameters are necessary to describe rescattering effects for Cabibbo forbidden D^0 decays, given the lack of experimental informations on isoscalar resonances. We keep their number to a minimum - three - using phenomenologically based considerations. We also discuss CP violating asymmetries.
Nonleptonic weak decays of charmed mesons
A previous analysis of two-body Cabibbo-allowed nonleptonic decays of D0 mesons and of Cabibbo-allowed and first-forbidden decays of D+ and Ds+ has been adjourned using more recent experimental data and extended to the Cabibbo-forbidden decays of D0. Annihilation and W-exchange contributions as well as final state interaction effects (assumed to be dominated by nearby resonances) have been included and are in fact crucial to obtain a reasonable agreement with the experimental data, which show large flavor SU(3) violations. New fitting parameters are necessary to describe rescattering effects for Cabibbo-forbidden D0 decays, given the lack of experimental information on isoscalar resonances. We keep their number to a minimum, three, using phenomenologically based considerations. We also discuss CP-violating asymmetries
Form factors of heavy mesons in QCD
Logarithmic corrections to form factors of mesons built from heavy quarks are dirived in the framework of quantum chromodynamics. The reactions e+e- → etasub(c)γ and H → J/PSIγ are considered as an example. A novel feature as compared to the well studied problem of the pion form factor is the existence of the transformations between the quark-antiquark state c anti c and the gluonic one. O(αsub(s)) corrections are calculated exactly. An infinite series of the leading logarithmic terms is summed up with the help of the operator technique. Apart from already known results for quark operators some new results referring to gluon operators and their mixing with the quark ones are used. Two alternative derivations of the multiplicatively renormalizable operators are given. The first one reduces to a direct computation of the mixing matrix and its diagonalization, the second derivation is based on conformal symmetry considerations
Radiative meson decays in chiral perturbation theory
Radiative meson decays are a fertile field for chiral perturbation theory. Chiral symmetry together with gauge invariance yield stringent constraints on radiative decay amplitudes. In addition to predicting decay rates and spectra, the chiral approach allows for a unified description of CP violation in radiative K decays. The chiral viewpoint in the recent controversy over the magnitude of two-photon exchange in the decay KL→ π0e+e- is exposed. The radiative decay η→π0γγ is discussed as an intriguing case where the leading result of chiral perturbation theory seems to be too small by two orders of magnitude in rate. 32 refs., 3 figs. (Author)
Open charm meson production at LHC*
Luszczak Marta
2012-12-01
Full Text Available We discuss charm production at the LHC. The production of single cc¯$car c$ pairs is calculated in the kt-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 cc¯ $car c$ within a simple formalism of double-parton scattering (DPS. Surprisingly large cross sections, comparable to single-parton scattering (SPS, are predicted for LHC energies. We discuss perspectives how to identify the double scattering contribution. We predict much larger cross section for large rapidity distance between charm quarks from different hard parton scatterings compared to single scattering.
Scaling Phenomenology in Meson Photoproduction from CLAS
In the high energy limit, perturbative QCD predicts that hard scattering amplitudes should follow simple scaling laws. For hard scattering at 90o, we show that experiments support this prediction even in the 'medium energy' regime of 2.3 GeV (le) √s (le) 2.84 GeV, as long as there are no s-channel resonances present. Our data consists of high statistics measurements for five different exclusive meson photoproduction channels (pω, pη, pη(prime), K+Λ and K+(summation)0) recently obtained from CLAS at Jefferson Lab. The same power-law scaling also leads to 'saturated' Regge trajectories at high energies. That is, at large -t and -u, Regge trajectories must approach constant negative integers. We demonstrate the application of saturated Regge phenomenology by performing a partial wave analysis fit to the γyp → pη(prime) differential cross sections.
Meson-proton scattering at high energies
We use a model in which the energy dependence of hadronic scattering is driven at high energies primarily by semihard scattering of constituent gluons and quarks to calculate the elastic differential and total cross sections for πp and Kp scattering. Our model predicts that, as a direct consequence of the dominance of gluon and sea-quark interactions at small x, the total cross sections for all the meson-proton processes should approach equality in the TeV energy regime. The cross sections are strikingly large for energies in the upper range of cosmic-ray energies, and the expected evolution of hadronic air showers may be changed as a result
B mesons phenomenology and lattice QCD
We have studied some phenomenological aspects of the B meson physics by using lattice QCD, which is a non perturbative method (based on the first principles of Quantum Field Theory) of computing Green functions of the theory. Pionic couplings g1 and g2, parameterizing the effective chiral Lagrangian which describes interactions between heavy-light mesons and soft pions, have been computed beyond the quenched approximation (at Nf = 2). We have renormalized the operator q-barγμγ5q non perturbatively by using chiral Ward identities. We obtain g1 = 0.4/0.6 and g2 = -0.1/-0.3. We have estimated from an un-quenched simulation (at Nf = 2) the strange quark mass: the non perturbative renormalisation scheme RI-MOM has been applied. After the matching in the MS scheme the result is ms(2 GeV) = 101 ± 8(-0,+25) MeV. We have proposed a method to calculate on the lattice the Heavy Quark Effective Theory form factors of the semileptonic transitions B → D** at zero recoil. The renormalisation constant of the operator h-barγiγ5Djh has been computed at one-loop order of the perturbation theory. We obtain τ1/2(1) = 0.3/0.5 and τ3/2(1) 0.5/0.7. Eventually the bag parameter BBs associated the Bs - Bs-bar mixing amplitude in the Standard Model has been estimated in the quenched approximation by using for the strange quark an action which verifies the chiral symmetry at finite lattice spacing a. Thus systematic errors are significantly reduced in the renormalisation procedure because the spurious mixing of the four-fermion operator h-barγμLqh-barγμLq with four-fermion operators of different chirality is absent. The result is BBs = 0.92(3). (author)
Production of charmed mesons in Z decays
Buskulic, D.; de Bonis, I.; Decamp, D.; Ghez, P.; Goy, C.; Lees, J.-P.; Minard, M.-N.; Pietrzyk, B.; Ariztizabal, F.; Comas, P.; Crespo, J. M.; Efthymiopoulos, I.; Fernandez, E.; Fernandez-Bosman, M.; Gaitan, V.; Garrido, Ll.; Mattison, T.; Orteu, S.; Pacheco, A.; Padilla, C.; Pascual, A.; Creanza, D.; de Palma, M.; Farilla, A.; Iaselli, G.; Maggi, G.; Marinelli, N.; Natali, S.; Nuzzo, S.; Ranieri, A.; Raso, G.; Romano, F.; Ruggieri, F.; Selvaggi, G.; Silvestris, L.; Tempesta, P.; Zito, G.; Chai, Y.; Hu, H.; Huang, D.; Huang, X.; Lin, J.; Wang, T.; Xie, Y.; Xu, D.; Xu, R.; Zhang, J.; Zhang, L.; Zhao, W.; Bonvicini, G.; Boudreau, J.; Casper, D.; Drevermann, H.; Forty, R. W.; Ganis, G.; Gay, C.; Girone, M.; Hagelberg, R.; Harvey, J.; Hilgart, J.; Jacobsen, R.; Jost, B.; Knobloch, J.; Lehraus, I.; Maggi, M.; Markou, C.; Martinez, M.; Mato, P.; Meinhard, H.; Minten, A.; Miquel, R.; Moser, H.-G.; Palazzi, P.; Pater, J. R.; Perlas, J. A.; Perrodo, P.; Pusztaszeri, J.-F.; Ranjard, F.; Rolandi, L.; Rothberg, J.; Ruan, T.; Saich, M.; Schlatter, D.; Schmelling, M.; Sefkow, F.; Tejessy, W.; Tomalin, I. R.; Veenhof, R.; Wachsmuth, H.; Wasserbaech, S.; Wiedemann, W.; Wildish, T.; Witzeling, W.; Wotschack, J.; Ajaltouni, Z.; Bardadin-Otwinowska, M.; Barres, A.; Boyer, C.; Falvard, A.; Gay, P.; Guicheney, C.; Henrard, P.; Jousset, J.; Michel, B.; Montret, J.-C.; Pallin, D.; Perret, P.; Podlyski, F.; Proriol, J.; Saadi, F.; Fearnley, T.; Hansen, J. B.; Hansen, J. D.; Hansen, J. R.; Hansen, P. H.; Johnson, S. D.; Møllerud, R.; Nilsson, B. S.; Kyriakis, A.; Simopoulou, E.; Siotis, I.; Vayaki, A.; Zachariadou, K.; Badier, J.; Blondel, A.; Bonneaud, G.; Brient, J. C.; Bourdon, B.; Fouque, G.; Passalacqua, L.; Rougé, A.; Rumpf, M.; Tanaka, R.; Verderi, M.; Videau, H.; Candlin, D. J.; Parsons, M. I.; Veitch, E.; Focardi, E.; Moneta, L.; Parrini, G.; Corden, M.; Delfino, M.; Georgiopoulos, C.; Ikeda, M.; Jaffe, D. E.; Levinthal, D.; Antonelli, A.; Bencivenni, G.; Bologna, G.; Bossi, F.; Campana, P.; Capon, G.; Cerutti, F.; Chiarella, V.; Felici, G.; Laurelli, P.; Mannocchi, G.; Murtas, F.; Murtas, G. P.; Pepe=Altarelli, M.; Salomone, S.; Colrain, P.; Ten Have, I.; Lynch, J. G.; Maitland, W.; Morton, W. T.; Raine, C.; Reeves, P.; Scarr, J. M.; Smith, K.; Smith, M. G.; Thompson, A. S.; Thorn, S.; Turnbull, R. M.; Brandl, B.; Braun, O.; Geweniger, C.; Graefe, G.; Hanke, P.; Hepp, V.; Karger, C.; Kluge, E. E.; Maumary, Y.; Putzer, A.; Rensch, B.; Stahl, A.; Tittel, K.; Wunsch, M.; Beuselinck, M.; Binnie, D. M.; Cameron, W.; Cattaneo, M.; Colling, D. J.; Dornan, P. J.; Hassard, J. F.; Lieske, N. M.; Moutoussi, A.; Nash, J.; Patton, S.; Payne, D. G.; Phillips, M. J.; San Martin, G.; Sedgbeer, J. K.; Wright, A. G.; Girtler, P.; Kuhn, D.; Rudolph, G.; Vogl, R.; Bowdery, C. K.; Brodbeck, T. J.; Finch, A. J.; Foster, F.; Hughes, G.; Jackson, D.; Keemer, N. R.; Nuttal, M.; Patel, A.; Sloan, T.; Snow, S. W.; Whelan, E. P.; Galla, A.; Greene, A. M.; Kleinknecht, K.; Raab, J.; Renk, B.; Sander, H.-G.; Schmidt, H.; Walther, S. M.; Wanke, R.; Wolf, B.; Bencheikh, A. M.; Benchouk, C.; Bonissent, A.; Calvet, D.; Carr, J.; Coyle, P.; Diaconu, C.; Drinkard, J.; Etienne, F.; Nicod, D.; Payre, P.; Roos, L.; Rousseau, D.; Schwemling, P.; Talby, M.; Adlung, S.; Assmann, R.; Bauer, C.; Blum, W.; Brown, D.; Cattaneo, P.; Dehning, B.; Dietl, H.; Dydak, F.; Frank, M.; Halley, A. W.; Jakobs, K.; Lauber, J.; Lütjens, G.; Lutz, G.; Männer, G.; Richter, R.; Schröder, J.; Schwarz, A. S.; Settles, R.; Seywerd, H.; Stierlin, H.; Stiegler, U.; Denis, R. St.; Wolf, G.; Alemany, R.; Boucrot, J.; Callot, O.; Cordier, A.; Davier, M.; Duflot, L.; Grivaz, J.-F.; Heusse, Ph.; Janot, P.; Kim, D. W.; Le Diberder, F.; Lefrançois, J.; Lutz, A.-M.; Musolino, G.; Schune, M.-H.; Veillet, J.-J.; Videau, I.; Abbaneo, D.; Bagliesi, G.; Batignani, G.; Bottigli, U.; Bozzi, C.; Calderini, G.; Carpinelli, M.; Ciocci, M. A.; Ciulli, V.; Dell'Orso, R.; Ferrante, I.; Fidecaro, F.; Foà, L.; Forti, F.; Giassi, A.; Giorgi, M. A.; Gregorio, A.; Ligabue, F.; Luisiani, A.; Mannelli, E. B.; Marrocchesi, P. S.; Messineo, A.; Palla, F.; Rizzo, G.; Sanguinetti, G.; Spagnolo, P.; Steinberger, J.; Tenchini, R.; Tonelli, G.; Triggiani, G.; Valassi, A.; Vannini, C.; Venturi, A.; Verdini, P. G.; Walsh, J.; Betteridge, A. P.; Gao, Y.; Green, M. G.; Johnson, D. L.; March, P. V.; Medcalf, T.; Mir, Ll. M.; Quazi, I. S.; Strong, J. A.; Bertin, V.; Botterill, D. R.; Clifft, R. W.; Edgecock, T. R.; Haywood, S.; Edwards, M.; Norton, P. R.; Thompson, J. C.; Bloch-Devaux, B.; Colas, P.; Duarte, H.; Emery, S.; Kozanecki, W.; Lançon, E.; Lemaire, M. C.; Locci, E.; Marx, B.; Perez, P.; Rander, J.; Renardy, J.-F.; Rosowsky, A.; Roussarie, A.; Schuller, J.-P.; Schwindling, J.; Si Mohand, D.; Vallage, B.; Johnson, R. P.; Litke, A. M.; Taylor, G.; Wear, J.; Babbage, W.; Booth, C. N.; Buttar, C.; Cartwright, S.; Combley, F.; Dawson, I.; Thompson, L. F.; Barberio, E.; Böhrer, A.; Brandt, S.; Cowan, G.; Grupen, C.; Lutters, G.; Rivera, F.; Schäfer, U.; Smolik, L.; Bosisio, L.; Della Marina, R.; Giannini, G.; Bobbo, B.; Pitis, L.; Ragusa, F.; Bellantoni, L.; Chen, W.; Conway, J. S.; Feng, Z.; Ferguson, D. P. S.; Gao, Y. S.; Grahl, J.; Harton, J. L.; Hayes, O. J.; Nachtman, J. M.; Pan, Y. B.; Saadi, Y.; Schmitt, M.; Scott, I.; Sharma, V.; Shi, Z. H.; Turk, J. D.; Walsh, A. M.; Weber, F. V.; Wu, Sau Lan; Wu, X.; Zheng, M.; Zobernig, G.
1994-03-01
The production of charmed mesonsmathop {D^0 }limits^{( - )} , D ± , and D *± is studied in a sample of 478,000 hadronic Z decays. The production rates are measured to be 10052_2005_Article_BF01559519_TeX2GIFE1.gif begin{gathered} {Γ (Z to D^{* ± } X)}/{Γ _{had }} = 0.187 ± 0.015(exp .) ± 0.013(BR), \\ {Γ (Z to D^ ± X)}/{Γ _{had }} = 0.251 ± 0.026(exp .) ± 0.025(BR), \\ {Γ (Z to mathop {D^0 }limits^{( - )} X)}/{Γ _{had }} = 0.518 ± 0.052(exp .) ± 0.035(BR), \\ where the errors from this analysis are separated from those coming from the D branching ratios (BR). The D *± momentum distribution is extracted separately forZ to cbar c andZ to bbar b events with the help of event shape variables. It is consistent with the prediction of the JETSET Monte Carlo program after adjustment of the charm fragmentation function. Constraining the shape of theZ to bbar b contribution, the average fraction of the beam energy taken by a D * meson produced in the fragmentation of a charm quark is extracted by a parametric fit to be c =0.495±0.011±0.007. Evidence for D **0 ( D 1(2420)0 and/or D {2/*}(2460)0) production is found in theD^{* ± } π ^ mp channel, accounting for a fraction (18±5±2)% of all D *± production. The relative production of vector and pseudoscalar mesons is dicussed, together with the possible effects of D ** production. The c-quark forward-backward Z-pole asymmetry is detrmined from that of high momentum D *± to be A {/FB 0,c }=(7.7±4.4)%.
Strong interaction physics: from quarks to mesons, baryons and nuclei
We summarize some of the important physics issues confronted at the NATO Advanced Research Workshop in Cracow. The topics addressed include modern challenges in understanding baryon and meson structure, hadronic interactions and hadron properties in dense matter. (author)
The Effect of Vector Meson Decays on Dihadron Fragmentation Functions
Matevosyan, Hrayr H; Bentz, Wolfgang
2014-01-01
Dihadron Fragmentation Functions (DFF) provide a vast amount of information on the intricate details of the parton hadronization process. Moreover, they provide a unique access to the "clean" extraction of nucleon transversity parton distribution functions in semi inclusive deep inelastic two hadron production process with a transversely polarised target. On the example of the u \\to \\pi^+ \\pi^-, we analyse the properties of unpolarised DFFs using their probabilistic interpretation. We use both the NJL-jet hadronization model and PYTHIA 8.1 event generator to explore the effect of the strong decays of the vector mesons produced in the quark hadronization process on the pseudoscalar DFFs. Our study shows that, even though it is less probable to produce vector mesons in the hadronization process than pseudo scalar mesons of the same charge, the products of their strong decays drastically affect the DFFs for pions because of the large combinatorial factors. Thus, an accurate description of both vector meson produ...
Enhancement of φ Mesons in Relativistic Nucleus-Nucleus Collisions
2002-01-01
The фmeson production in relativistic nucleus-nucleus collisions is investigated systematically usinga hadron-string cascade model LUCIAE. Within the framework of the model and relying on the collective
Chiral symmetry and scalar meson in hadron and nuclear physics
Kunihiro, T
1995-01-01
After giving a short introduction to the Nambu-Jona-Lasinio model with an anomaly term, we show the importance of the scalar-scalar correlation in the low-energy hadron dynamics, which correlation may be summarized by a scalar-isoscalar meson, the sigma meson. The discussion is based on the chiral quark model with the sigma-meson degrees of freedom. Possible experiments are proposed to produce the elusive meson in a nucleus and detect it. In relation to a precursory soft mode for the chiral transition, the reason is clarified why the dynamic properties of the superconductor may be described by the diffusive time-dependent Ginzburg-Landau (TDGL) equation. We indicate the chiral symmetry plays a significant role also in nuclei; one may say that the stability of nuclei is due to the chiral symmetry of QCD.
Exotic Behavior of Heavy-Flavored Meson Matter
Abreu, L M; da Silva, R Rodrigues
2012-01-01
In this work, we study the thermodynamic behavior of heavy-flavored meson matter in the framework of $(\\sigma,\\omega)$-meson-exchange model in relativistic mean field theory. We find a decreasing of the effective masses of $D$ and $B$ mesons as the temperature increases. By using the effective mass and maximum value of dissociation temperatures available from lattice QCD, the masses of the bound states $D \\bar{D}$ and $B \\bar{B}$ are estimated in 2 MeV for both molecules. For the $B$-meson matter, the pressure presents an exotic behavior, being negative for temperatures above 6.6 times the deconfinement transition temperature $T_c$. In addition, the ratio of pressure to energy density is similar to the value predicted for systems that behave as dark energy matter.
Scalar mesons in a chiral quark model with glueball
Ground-state scalar isoscalar mesons and a scalar glueball are described in a U(3)xU(3) chiral quark model of the Nambu-Jona-Lasinio (NJL) type with 't Hooft interaction. The latter interaction produces singlet-octet mixing in the scalar and pseudoscalar sectors. The glueball is introduced into the effective meson Lagrangian as a dilaton on the basis of scale invariance. The mixing of the glueball with scalar isoscalar quarkonia and amplitudes of their decays into two pseudoscalar mesons are shown to be proportional to current quark masses, vanishing in the chiral limit. Mass spectra of the scalar mesons and the glueball and their main modes of strong decay are described
Sigma meson production in proton-nucleus collisions
The sigma meson production is investigated in p + 40Ca and p + 208Pb at the incident energy 1.5 GeV within the Quantum Molecular Dynamics model. The simulation results indicate a distinctive A dependence of the sigma production that the increase of A is followed by an increase of the production cross section. We find that the sigma meson production is strongly medium dependent and the produced sigma mesons decaying in a dense medium experience a stronger mass shift towards lower masses. This mass shift is an experimentally accessible observable in the final state pion pairs, which did not suffer absorption by the surrounding nucleons. It is pointed out that the ratio of measured sigma cross-sections as a function of the sigma invariant-mass from various reactions is a good probe to explore the existence of the sigma meson in dense nuclear environment. (author)
pi K scattering in effective chiral theory of mesons
Li, Bing An; Gao, Dao-Neng; Yan, Mu-Lin
1998-01-01
In the framework of an effective chiral theory of mesons, pi K scattering is stydied. The scattering lengths, phase shifts, and cross sections are calculated. Theoretical results agree well with data. There is no new parameter in this study.
Vector Mesons and Baryon Resonances in Nuclear Matter
Post, M.; Mosel, U.
2001-01-01
We calculate the effect of many-body interactions in nuclear matter on the spectral function of $\\rho$ and $\\omega$ meson. In particular, we focus on the role played by baryon resonances in this context.
Lattice results on the meson electric form factor
A calculation is outlined and results presented for the electric form factor, measured at two values of the momentum, of the pseudo-Goldstone meson within the staggered formulation of lattice fermions
Modernization of meson channels of the JINR LNP Phasotron
At the JINR LNP Phasotron, modernization of beamline T and meson beam channels 1, 2 and 3, for expansion of realization opportunities of physical researches on meson beams, was carried out. Parameters of existing beams were improved and new ones were generated. As a result of the modernization due to optimization of angles of secondary particle selection from targets and installation of additional lenses and magnets, the intensity of positive π meson beams on channel 3 has grown 3-40 times in the energy range 100-400 MeV and has run up to 3·107 s-1 per 1 μA intensity of the extracted proton beam. The maximum intensity of the π- meson beam in this range has reached 5·106 s-1 per 1 μA intensity of the extracted beam. On channels 1, 2 and 3 due to creation of stationary vacuum from the chamber of the phasotron with a branching on all beamlines of the mesons up to their end and accommodation in vacuum of two target stations, production of meson beams with momentum < 50 MeV/c, including surface muons with energy near 4 MeV, was made possible. Occurrence of conditions for formation of a narrow (focused on the meson targets in a horizontal plane up to 2-3 mm) proton beam allowed one to reduce 2-3 times the impurity of electronic or positronic components in all meson beams, and for beams of slow π mesons on channel 3 (10-40 MeV) the admixture of electron-positron components reduced 10-15 times due to increase of the angle of selection of π mesons up to 110 deg on the second target station. It became possible to apply small (∼ 80 mm) target from heavy elements for which the π-meson yield with a moment of about 100 MeV/c increased 2-4.5 times in comparison with a beryllium target of the identical size. (author)
Meson decay constants from Nf=2 clover fermions
We present recent results for meson decay constants calculated on configurations with two flavours of O(a)-improved Wilson fermions. Non-perturbative renormalisation is applied and quark mass dependencies as well as finite volume and discretisation effects are investigated. In this work we also present the first computation of the coupling of the light vector mesons to the tensor current using dynamical fermions. (orig.)
Rho-0 Meson Helicity Amplitude Ratios at HERMES
Murray, Morgan
2012-01-01
The study of {\\rho}0 meson helicity amplitude ratios at HERMES shows that the amplitude hierarchy expected from pQCD is confirmed. The contribution of Unnatural Parity Exchange in the production of {\\rho}0 mesons is significant at HERMES kinematics and there is a large phase-difference in the leading F11 and F01 amplitudes. The kinematic dependences of the amplitude ratios only sometimes follow theory-based expectations.
Search for the Bc(2S) meson at CMS
Alves, Bruno
2016-01-01
The work was developed during the CERN Summer Student Programme, from June 27th to September 14th. We looked for the excited state of the Bc meson that has already been found in the ATLAS experiment. Optimized cuts were obtained both for the Bc and for the Bc(2S) mesons. The final results are not conclusive, but indicate the presence of a signal. Run 2 data set (2015-2016) is required.
Two-phase model with vector-meson stabilization
We present a topological chiral two-phase model for baryons with isoscalar vector meson stabilizing term in the soliton sector instead of the usual Skyrme stabilizing term and compare with a closely related model where the omega meson has been eliminated in the limit of infinite mass and coupling constant. In both cases the static properties come out well and the energy is insensitive to changes in the bag radius, as in other nonperturbative two-phase models. (orig.)
Light Scalar Mesons in Photon-Photon Collisions
Achasov, N. N.; Shestakov, G. N.
2009-01-01
The light scalar mesons, discovered over forty years ago, became a challenge for the naive quark-antiquark model from the outset. At present the nontrivial nature of these states is no longer denied practically anybody. Two-photon physics has made a substantial contribution to understanding the nature of the light scalar mesons. Recently, it entered a new stage of high statistics measurements. We review the results concerning two-photon production mechanisms of the light scalars, based on the...
Meson spectra governed by the Fermi-Breit potential
Jirimutu; WANG Hai-Jun; ZHANG Wei-Ning; Cheuk-Yin Wong
2009-01-01
We calculate the meson mass spectra in a quark potential model by using the complete Fermi-Breit potential including the terms of orbit-orbit interaction, spin-orbit coupling, and tensor force interaction. We find that these terms give nontrivial contributions to the calculated meson spectra. The orbit-orbit coupling term may lead to an instability of the solution of the Schrodinger equation and should be regularized.
Meson structure in the next-to-leading order
We present here a general scheme for accessing informations about the meson structure. The idea is based on calculating the structure of a constituent quark, which is common to all hadrons. The method is applied to pion and kaon as an example. While there is only a scarce data on the ratio of up-quark valence distributions of the K+ and π+ mesons, our model calculation nicely agrees with the data. (orig.)
Using anti pp annihilation to find exotic mesons
Sharpe, S.R.
1987-10-01
Present data suggests that a number of mesons have been found which cannot be accommodated in standard anti qq multiplets. Theory suggests that such exotic mesons should exist in the spectrum of Quantum Chromodynamics, but provides little guide to their properties. It is argued that a high luminosity, low energy anti pp machine would be a powerful tool with which to search for such exotics.
Using anti pp annihilation to find exotic mesons
Present data suggests that a number of mesons have been found which cannot be accommodated in standard anti qq multiplets. Theory suggests that such exotic mesons should exist in the spectrum of Quantum Chromodynamics, but provides little guide to their properties. It is argued that a high luminosity, low energy anti pp machine would be a powerful tool with which to search for such exotics
Puzzle of vector mesons: solution with account of multiquark states
Strong decays of vector mesons above 1 GeV are discussed in the framework of the quark model. A scenario is proposed to resolve the situation with branching ratios by means of the concept of q2q2 states coupled to qantiq mesons. The branching ratios of ρ(1450) and ρ(1700) as well as ρ1(1270) and C(1480) may be qualitatively explained in the presented picture
Two-Particle Correlations and Meson-Antimeson Mixing Effects
Dass, G. V.; Grimus, W.
1999-01-01
We discuss 2-particle correlations which arise in the time evolution of C-odd and C-even meson--antimeson states of flavoured neutral mesons. In order to keep our discussion general, we do not use the Weisskopf -- Wigner approximation. Possible deviations from quantum-mechanical coherence effects are parameterized by a so-called decoherence parameter $\\zeta$. In particular, we study the $\\zeta$-dependence of the asymmetry of unlike and like-flavoured events which was recently observed experim...
Magnetic dipole moments of the heavy tensor mesons in QCD
The magnetic dipole moments of the D2, and DS2, B2, and BS2 heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors
Magnetic dipole moments of the heavy tensor mesons in QCD
The magnetic dipole moments of the D2, and DS2, B2, and BS2 heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors. (orig.)
Actual interpretation of recent results on meson photoproduction
Actual ideas to remove existing discrepancies between photoproduction and e+e--production on searching radially excited ρ-mesons will be discussed. An update of a candidates list for corresponding ω and φ excitations is given. Photoproduction properties of two possibly exotic states are presented: A meikton-state decaying into b1(1235)π and the well known a0(980) meson. (orig.)
Multiparticle production in the decays of the B-meson
Dobrovolskaya, A.V.; Kaidalov, A.B.; Ter-Martirosyan, K.A.; Zoller, V.R. (Institut Teoreticheskoj i Ehksperimental' noj Fiziki, Moscow (USSR))
1989-10-12
In the framework of the 1/N{sub f} expansion and the quark-gluon strings model partial widths of nonleptonic and semileptonic multiparticle channels of B-meson decays are calculated for both b->c and b->u transitions. The distribution on the number of charged mesons for a given number n{sub 0} of neutral pions is presented. (orig.).
Magnetic dipole moments of the heavy tensor mesons in QCD
Aliev, T. M., E-mail: taliev@metu.edu.tr [Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Institute of Physics, Baku (Azerbaijan); Barakat, T., E-mail: tbarakat@KSU.EDU.SA [Physics Department, Middle East Technical University, 06531, Ankara (Turkey); Physics and Astronomy Department, King Saud University, Riyadh (Saudi Arabia); Savcı, M., E-mail: savci@metu.edu.tr [Physics Department, Middle East Technical University, 06531, Ankara (Turkey)
2015-11-03
The magnetic dipole moments of the D{sub 2}, and D{sub S{sub 2}}, B{sub 2}, and B{sub S{sub 2}} heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors.
$\\phi$-meson production in proton-proton collisions
K Nakayama; Durso, J.W.; J. Haidenbauer(IKP - Julich); Hanhart, C.; Speth, J.(Institut für Kernphysik, Forschungszentrum Jülich, Jülich, D-52425, Germany)
1999-01-01
The production of $\\phi$-mesons in proton-proton collisions is investigated within a relativistic meson-exchange model of hadronic interactions. The experimental prerequisites for extracting the $NN\\phi$ coupling strength from this reaction are discussed. In the absence of a sufficient set of data, which would enable an accurate determination of the $NN\\phi$ coupling strength, we perform a combined analysis, based on some reasonable assumptions, of the existing data for both $\\omega$- and $\\p...
Spatial dependence of the finite-temperature meson correlation function
The spatial dependence of the finite-temperature meson correlation functions is studied in detail. The calculations are based on the first order expression of the perturbative QCD. From the asymptotic behaviour of the correlation function we read off the values of the meson screening masses which are in agreement with the Eletskii and Ioffe limit: mscr = 2πT. The problems connected with the regularization of the diverging expressions are discussed thoroughly. (author). 9 refs, 3 figs
Magnetic dipole moments of the heavy tensor mesons in QCD
Aliev, T M; Savcı, M
2015-01-01
The magnetic dipole moments of the ${\\cal D}_2$, and ${\\cal D}_{S_2}$, ${\\cal B}_2$, and ${\\cal B}_{S_2}$ heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the $SU(3)$ flavor symmetry violation is about 10\\% in both $b$ and $c$ sectors.
Double meson production in ultraperipheral heavy-ion collisions
The double-meson production in ultraperipheral heavy-ions collisions is addressed, focusing on the particular case of ρJ/Ψ from two-photon reactions. The cross section at photon level is obtained using distinct parameterizations for the gluon distribution on the light meson. The resulting estimates for the nuclear case are presented and discussed. As a by-product, we estimate the double ρ production cross section using the pomeron-exchange factorization relations. (orig.)
Double meson production in ultraperipheral heavy ion collisions
Goncalves, V. P.; Machado, M. V. T.
2003-01-01
The double meson production in ultraperipheral heavy ions collisions is addressed, focusing on the particular case of rho-J/Psi from two-photon reactions. The cross section at photon level is obtained using distinct parameterizations for the gluon distribution on the light meson. The resulting estimates for the nuclear case are presented and discussed. As a by product, we estimate the double rho production cross section using the Pomeron-exchange factorization relations.
Properties of mesons in a strong magnetic field
Zhang, Rui; Fu, Wei-jie; Liu, Yu-xin
2016-06-01
By extending the Φ -derivable approach in the Nambu-Jona-Lasinio model to a finite magnetic field we calculate the properties of pion, σ , and ρ mesons in a magnetic field at finite temperature not only in the quark-antiquark bound state scheme but also in the pion-pion scattering resonant state scenario. Our calculation as a result makes manifest that the masses of π 0 and σ meson can be nearly degenerate at the pseudo-critical temperature which increases with increasing magnetic field strength, and the π ^{± } mass ascends suddenly at almost the same critical temperature. Meanwhile the ρ mesons' masses decrease with the temperature but increase with the magnetic field strength. We also check the Gell-Mann-Oakes-Renner relation and find that the relation can be violated clearly with increasing temperature, and the effect of the magnetic field becomes pronounced around the critical temperature. With different criteria, we analyze the effect of the magnetic field on the chiral phase transition and find that the pseudo-critical temperature of the chiral phase cross, T_c^{χ }, is always enhanced by the magnetic field. Moreover, our calculations indicate that the ρ mesons will get melted as the chiral symmetry has not yet been restored, but the σ meson does not disassociate even at very high temperature. Particularly, it is the first to show that there does not exist a vector meson condensate in the QCD vacuum in the pion-pion scattering scheme.
Phenomenology of charmed mesons in the extended linear sigma model
We study the so-called extended linear sigma model for the case of four quark flavors. This model is based on global chiral symmetry and dilatation invariance and includes, besides scalar and pseudoscalar mesons, vector and axial-vector mesons. Most of the parameters of the model have been determined in previous work by fitting properties of mesons with three quark flavors. Only three new parameters, all related to the current charm quark mass, appear when introducing charmed mesons. Surprisingly, within the accuracy expected from our approach, the masses of open charmed mesons turn out to be in quantitative agreement with experimental data. On the other hand, with the exception of J/ψ, the masses of charmonia are underpredicted by about 10%. It is remarkable that our approach correctly predicts (within errors) the mass splitting between spin-0 and spin-1 negative-parity open charm states. This indicates that, although the charm quark mass breaks chiral symmetry quite strongly explicitly, this symmetry still seems to have some influence on the properties of charmed mesons. (orig.)
Mesons in strong magnetic fields: (I) General analyses
Hattori, Koichi; Su, Nan
2015-01-01
We study properties of neutral and charged mesons in strong magnetic fields |eB|>> Lambda_QCD^2 with Lambda_QCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger-Dyson and Bethe-Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B^2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compare...
Mesons in strong magnetic fields: (I) General analyses
Hattori, Koichi; Kojo, Toru; Su, Nan
2016-07-01
We study properties of neutral and charged mesons in strong magnetic fields | eB | ≫ ΛQCD2 with ΛQCD being the QCD renormalization scale. Assuming long-range interactions, we examine magnetic-field dependences of various quantities such as the constituent quark mass, chiral condensate, meson spectra, and meson wavefunctions by analyzing the Schwinger-Dyson and Bethe-Salpeter equations. Based on the density of states obtained from these analyses, we extend the hadron resonance gas (HRG) model to investigate thermodynamics at large B. As B increases the meson energy behaves as a slowly growing function of the meson's transverse momenta, and thus a large number of meson states is accommodated in the low energy domain; the density of states at low temperature is proportional to B2. This extended transverse phase space in the infrared regime significantly enhances the HRG pressure at finite temperature, so that the system reaches the percolation or chiral restoration regime at lower temperature compared to the case without a magnetic field; this simple picture would offer a gauge invariant and intuitive explanation of the inverse magnetic catalysis.
On Decays of B Mesons to a Strange Meson and an Eta or Eta' Meson at Babar
Hirschauer, James Francis; /SLAC
2009-04-21
We describe studies of the decays of B mesons to final states {eta}K{sup *}(892), {eta}K{sup *}{sub 0}(S-wave), {eta}K{sup *}{sub 2}(1430), and {eta}'K based on data collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collier at the Stanford Linear Accelerator Center. We measure branching fractions and charge asymmetries for the decays B {yields} {eta}K{sup *}, where K{sup *} indicates a spin 0, 1, or 2 K{pi} system, making first observations of decays to final states {eta}K{sup *0}{sub 0}(S-wave), {eta}K{sup *+}{sub 0} (S-wave), and {eta}K{sup *0}{sub 2}(1430). We measure the time-dependent CP-violation parameters S and C for the decays B{sup 0} {yields} {eta}'K{sup 0}, observing CP violation in a charmless B decay with 5{sigma} significance considering both statistical and systematic uncertainties..
{eta} meson photoproduction on deuterium; Photoproduction du meson {eta} sur le deuterium
Hoffmann-Rothe, P.
1996-05-30
Measurements of the total and differential cross sections for {eta}-meson photoproduction on a D{sub 2} liquid target from threshold to 1.2 GeV, have been taken using the tagged Bremsstrahlung photon beam produced by the electrons extracted from the ELSA storage ring at Bonn. The reaction was identified by detecting the eta decay products in the neutral meson spectrometer SPES0-2{pi}, while the recoil baryons (proton, neutron or deuteron) were detected by a variety of large angle scintillator detectors. We succeeded to identify completely the final states corresponding to the production of an {eta} meson on a Quasi-Free (QF) proton, a QF neutron and the coherent deuteron. The differential cross sections corresponding to the production of a coherent deuteron n the final state have been measured, from threshold to 800 MeV; they are 6 times smaller the only previous measurement reported by Anderson and Prepost in 1969. This is consistent with an Isoscalar part of the Amplitude much smaller than the Isovector one. The differential cross sections are in good agreement with the theoretical prediction on the impulse approximation mechanism; indicating in particular, fairly small contributions from rescattering terms. A direct measurement of the neutron to proton cross section ratios has been obtained by integrating the counting rates on the corresponding QF peaks and is 0.70 {+-} 0.03, from 700 MeV to 900 MeV, with a small angular dependence. These two results by comparison to the measured free proton data should allow to reconstruct the free neutron cross sections in a rather model-independent way. (authors). 56 refs., 90 figs., 13 tabs.
Perturbative QCD study of $B_s$ decays to a pseudoscalar meson and a tensor meson
Qin, Qin; Zou, Zhi-Tian; Yu, Xin; Li, Hsiang-nan; Lü, Cai-Dian
2014-01-01
We study two-body hadronic Bs→PT decays, with P(T) being a light pseudoscalar (tensor) meson, in the perturbative QCD approach. The CP-averaged branching ratios and the direct CP asymmetries of the ΔS=0 modes are predicted, where Δ S is the difference between the strange numbers of final and initial states. We also define and calculate experimental observables for the ΔS=1 modes under the Bs0–B¯s0 mixing, including CP averaged branching ratios, time-integrated CP asymmetries, and the CP obser...
Description of the a0/f0 mesons with the Juelich model
Recently we have developed meson-exchange models for ππ and πη scattering and we have used them for investigating the nature of the meson resonances f0(980) and a0(980). These models are based on an effective meson Lagrangian utilising the symmetries of the QCD-Lagrangian as guideline. The resulting potential for meson-meson scattering contains t-channel vector-meson exchanges (ρ, K*, ω, φ) as well as s-channel pole diagrams (ρ, element of (1400), f2(1270)) and is iterated in a three-dimensional scattering equation of Blankenbecler-Sugar type. (orig.)
Heavy mesons spectroscopy and new quarks
The spectroscopy of new heavy mesons with masses above 2.8 GeV in the context of the asymptoticallty free gauge theories is analysed. To this end a power -law confinement potential is chosen. It is shown that the charmonium spectroscopy is best described by a potential where the exponent is around 0.5. It is observed that the spin-spin interaction is problematic. A possible interpretation of the γ resonances in the neighbourhood of 10 GeV is also discussed. The possible consequences of the existence of heavy quarks beyond charm with special reference to the processes initiated by neutral currents is also discussed. The present results on processes initiated by neutral current effects does not require introduction of right-handed heavy quarks beyond charm. Inclusion of the sea-quark contribution improves the agreements of the results of the Salam-Weinberg model with the recently observed results from CERN where 'ν anomaly' was not seen. The recently discovered γ resonances probably indicate the existence of heavy quarks probably with left handed coupling. Some preliminary study of this possibility was also carried out. (Author)
Dark photons from charm mesons at LHCb
Ilten, Philip; Williams, Mike; Xue, Wei
2015-01-01
We propose a search for dark photons $A^{\\prime}$ at the LHCb experiment using the charm meson decay $D^*(2007)^0 \\!\\to D^0 A^{\\prime}$. At nominal luminosity, $D^{*0} \\!\\to D^0 \\gamma$ decays will be produced at about 700kHz within the LHCb acceptance, yielding over 5 trillion such decays during Run 3 of the LHC. Replacing the photon with a kinetically-mixed dark photon, LHCb is then sensitive to dark photons that decay as $A^{\\prime}\\!\\to e^+e^-$. We pursue two search strategies in this paper. The displaced strategy takes advantage of the large Lorentz boost of the dark photon and the excellent vertex resolution of LHCb, yielding a nearly background-free search when the $A^{\\prime}$ decay vertex is significantly displaced from the proton-proton primary vertex. The resonant strategy takes advantage of the large event rate for $D^{*0} \\!\\to D^0 A^{\\prime}$ and the excellent invariant mass resolution of LHCb, yielding a background-limited search that nevertheless covers a significant portion of the $A^{\\prime}...
Photoproduction of {\\omega} Mesons off the Proton
Wilson, A; Anisovich, A V; Bacelar, J C S; Bantes, B; Bartholomy, O; Bayadilov, D; Beck, R; Beloglazov, Y A; Brinkmann, K T; Castelijns, R; Dutz, H; Elsner, D; Ewald, R; Frommberger, F; Fuchs, M; Funke, Chr; Gregor, R; Gridnev, A; Gutz, E; Hannappel, J; Hillert, W; Hoffmeister, P; Horn, I; Jaegle, I; Jude, T; Junkersfeld, J; Kalinowsky, H; Kleber, V; Klein, Frank; Klein, Friedrich; Klempt, E; Kotulla, M; Krusche, B; Lang, M; Löhner, H; Lopatin, I V; Lugert, S; Mertens, T; Messchendorp, J G; Metag, V; Nanova, M; Nikonov, V A; Novinski, D; Novotny, R; Ostrick, M; Pant, L M; van Pee, H; Pfeiffer, M; Roy, A; Sarantsev, A V; Schmidt, C; Schmieden, H; Shende, S; Sokhoyan, V; Sparks, N; Süle, A; Sumachev, V V; Szczepanek, T; Thoma, U; Trnka, D; Varma, R; Walther, D; Wendel, Ch; Wiedner, U
2015-01-01
The differential cross sections and unpolarized spin-density matrix elements for the reaction $\\gamma p\\to p\\omega$ were measured using the CBELSA/TAPS experiment for initial photon energies ranging from the reaction threshold to 2.5 GeV. These observables were measured from the radiative decay of the $\\omega$ meson, $\\omega\\to\\pi^0\\gamma$. The cross sections cover the full angular range and show the full extent of the $t$-channel forward rise. The overall shape of the angular distributions in the differential cross sections and unpolarized spin-density matrix elements are in fair agreement with previous data. In addition, for the first time, a beam of linearly-polarized tagged photons in the energy range from 1150 MeV to 1650 MeV was used to extract polarized spin-density matrix elements. These data were included in the Bonn-Gatchina partial wave analysis (PWA). The dominant contribution to $\\omega$ photoproduction near threshold was found to be the $3/2^+$ partial wave, which is primarily due to the sub-thr...
Dark photons from charm mesons at LHCb
Ilten, Philip; Thaler, Jesse; Williams, Mike; Xue, Wei
2015-12-01
We propose a search for dark photons A' at the LHCb experiment using the charm meson decay D*(2007 )0→D0A'. At nominal luminosity, D*0→D0γ decays will be produced at about 700 kHz within the LHCb acceptance, yielding over 5 trillion such decays during Run 3 of the LHC. Replacing the photon with a kinetically mixed dark photon, LHCb is then sensitive to dark photons that decay as A'→e+e-. We pursue two search strategies in this paper. The displaced strategy takes advantage of the large Lorentz boost of the dark photon and the excellent vertex resolution of LHCb, yielding a nearly background-free search when the A' decay vertex is significantly displaced from the proton-proton primary vertex. The resonant strategy takes advantage of the large event rate for D*0→D0A' and the excellent invariant-mass resolution of LHCb, yielding a background-limited search that nevertheless covers a significant portion of the A' parameter space. Both search strategies rely on the planned upgrade to a triggerless-readout system at LHCb in Run 3, which will permit the identification of low-momentum electron-positron pairs online during data taking. For dark photon masses below about 100 MeV, LHCb can explore nearly all of the dark photon parameter space between existing prompt-A' and beam-dump limits.
Determination of the D mesons lifetimes
The results from the experiment NA27, performed in the North Area of the Super Proton Synchrotron at CERN are presented. The experimental set up was the small, high resolution, rapid cyling bubble chamber LEBC coupled with the European Hybrid Spectrometer (EHS). More than 2 millions pictures were taken, with 1015000 in teractions in hydrogen. The stastistical sensitivity of the experiment was 38.5 events/μb. A clean sample of 700 charm particle decays was obtained. Estimators with minimal systematic and statistical errors are developed for the determination of the lifetimes of short-lived particles whose individual momenta are unknown. These estimators make use of the measured decay lengths and the a priori known production characteristics. In this way, it is possible to include identified but not fully reconstructed charm decays in the sample to determine their lifetime. The properties of these estimators were extensively studied by means of Montecarlo simulation. The detection of the short-lived particles through the impact parameter of their charged decay products leads to additional complications which are taken into account. The biases and statistical errors inherent in using simpler approximate lifetime estimators are also discussed. These estimators are applied to determine the lifetime of the Do and D+- mesons using the charm data sample from NA27. (Author)
Precision Studies of Light Mesons at COMPASS
Ketzer, Bernhard
2014-01-01
The COMPASS experiment at CERN's SPS investigates the structure and excitations of strongly interacting systems. Using reactions of 190 GeV/c pions with protons and nuclear targets, mediated by the strong and electromagnetic interaction, an unprecedented statistical precision has been reached allowing new insight into the properties of light mesons. For the first time the diffractively produced 3pi final state has been analyzed simultaneously in bins of invariant mass and four-momentum transfer using a large set of 88 waves up to a total angular momentum of 6. In addition to a precise determination of the properties of known resonances and including a model-indepedent analysis of the pi pi S-wave isobar, a new narrow axial-vector state coupling strongly to f0(980)pi has been found in previously unchartered territory. By selecting reactions with very small four-momentum transfer COMPASS is able to study processes involving the exchange of quasi-real photons. These provide clean access to low-energy quantities ...
Precision for B-meson matrix elements
Guazzini, D.; Sommer, R. [Deutsches Elektronen-Synchrotron (DESY), Zeuthen (Germany); Tantalo, N. [INFN sezione ' ' Tor Vergata' ' , Rome (Italy)]|[Centro E. Fermi, Rome (Italy)
2007-10-15
We demonstrate how HQET and the Step Scaling Method for B-physics, pioneered by the Tor Vergata group, can be combined to reach a further improved precision. The observables considered are the mass of the b-quark and the B{sub s}-meson decay constant. The demonstration is carried out in quenched lattice QCD. We start from a small volume, where one can use a standard O(a)-improved relativistic action for the b-quark, and compute two step scaling functions which relate the observables to the large volume ones. In all steps we extrapolate to the continuum limit, separately in HQET and in QCD for masses below m{sub b}. The physical point m{sub b} is then reached by an interpolation of the continuum results in 1/m. The essential, expected and verified, feature is that the step scaling functions have a weak mass-dependence resulting in an easy interpolation to the physical point. With r{sub 0}=0.5 fm and the experimental B{sub s} and K masses as input, we find F{sub B{sub s}}=191(6) MeV and the renormalization group invariant mass M{sub b}=6.88(10) GeV, translating into anti m{sub b}(anti m{sub b})=4.42(6) GeV in the MS scheme. This approach seems very promising for full QCD. (orig.)
This article is dedicated to the memory of Andrei D. Sakharov, a great scientist and human rights activist. Sakharov was blessed with the rare gift of prophetic prediction in matters concerning both science and society. His paper in 1967 on the baryon asymmetry of the universe relating it to the baryon instability, CP-violation, and thermodynamic non-equilibrium, was a very long shot. In view of subsequent theoretical developments in grand unified theories of elementary particle physics and cosmology, where the Sakharov conditions can be accommodated, this paper represents indeed a very fine example of scientific genius and prophecy. His political judgement, exemplified by his visionary essay Progress, Coexistence, and Intellectual Freedom, written in 1968, was equally stunning. Among other topics Sakharov was also very much interested in physics of the heavy quarks. In this paper we review theoretical predictions about an interesting aspect of heavy quark physics, namely rare phenomena in the decays of B-meson involving flavor changing neutral current (FCNC) processes
Photoproduction of Mesons off Light Nuclei
During the last few years, a series of experiments has been done at the ELSA accelerator in Bonn with the Crystal Barrel/TAPS setup and at the MAMI accelerator in Mainz with the Crystal Ball/TAPS setup. Photoproduction of light mesons off the deuteron and 3He-nuclei has been studied in detail. We will report some of the most interesting results.A completely unexpected finding, is the pronounced structure in the excitation function of the γn → nη reaction around 1 GeV, which has no counterpart for the proton. Recent measurements at GRAAL, Sendai, ELSA [1] and MAMI estimate it's width below 50 MeV, which would be extremely narrow for a nucleon resonance at this excitation energy. In the experiment with the 3He target, special attention was given to the threshold behavior of the γHe3 reactions in view of possible indications for the formation of (quasi-)bound η-nucleus states, so-called η-mesic nuclei. A very strong threshold enhancement of coherent η-photoproduction off 3He was found. In a new experiment, this reaction was measured with much better statistical accuracy compared to an earlier experiment at MAMI-B using the TAPS detector [2].
Inclusive radiative B meson decays at Belle
Improved measurement of inclusive radiative B meson decays We report a fully inclusive measurement of the flavor changing neutral current decay B → Xs γ in the energy range 1.7 GeV ≤ Ecms γ ≤ 2.8 GeV, covering 97 % of the total spectrum, where c.m.s. is the center of mass system. Using 605 fb-1 of data we obtain measurements of the partial branching fraction and first and second moments of the photon energy spectrum for lower energy thresholds including and above 1.7 GeV. Improved Measurement of the Electroweak Penguin Process B → Xsl+l-. We present a measurement of the branching fraction for the electroweak penguin process B → Xsl+l-, where l is an electron or a muon and Xs is a hadronic system containing an s-quark. The Xs hadronic system is reconstructed with one K± or K0s and up to four pions, where at most one pion can be neutral. The measurement is based on a data sample four times larger than used in the previous analysis, accumulated at the Υ(4S) resonance with the Belle detector at the KEKB e+e- asymmetric-energy collider. (author)
Leskovec, Luka; Mohler, Daniel; Prelovsek, Sasa; Woloshyn, R M
2015-01-01
We study the positive parity charmed strange mesons using lattice QCD, the only reliable ab initio method to study QCD at low energies. Especially the experimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged theory for quite some time. The dynamical lattice QCD simulations are performed at two distinct pion masses, $m_{\\pi}$ = 266 MeV and 156 MeV, using both $\\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction of the correlation matrix in order to take into the account threshold effects. While the $J^P = 0^+$ channel benefited most from the inclusion of scattering operators, it was also crucial for the case of the $D_{s1}(2460)$. Using the L\\"uscher method, which relates the finite volume spectrum to the infinite volume scattering matrix, we were able to determine the near threshold behavior of the scattering amplitude. From it we extracted the binding momenta and the masses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ by determining the ...
Electromagnetic Studies of Mesons, Nucleons, and Nuclei
Baker, Oliver K.
2013-08-20
Professor Baker was a faculty member at Hampton University in Hampton, Virginia, and, jointly, a Staff Physicist at Jefferson Lab in nearby Newport News from September 1989 to July 2006. The Department of Energy (DOE) funded the grant DE-FG02-97ER41035 Electromagnetic Studies of Mesons, Nucleons, and Nuclei, while Baker was in this joint appointment. Baker sent a closeout report on these activities to Hampton University’s Sponsored Research Office some years ago, shortly after joining Yale University in 2006. In the period around 2001, the research grant with Baker as the Principal Investigator (PI) was put under the supervision of Professor Liguang Tang at Hampton University. Baker continued to pursue the research while in this join appointment, however the administrative responsibilities with the DOE and with Hampton University rested with Professor Tang after 2001, to my recollection. What is written in this document is from Baker’s memory of the research activities, which he has not pursued since joining the Yale University faculty.
Bottomonium Mesons and Strategies for Their Observation
Godfrey, Stephen
2015-01-01
The B-factories and Large Hadron Collider experiments have demonstrated the ability to observe and measure the properties of bottomonium mesons. In order to discover missing states it is useful to know their properties to develop a successful search strategy. To this end we calculate the masses and decay properties of excited bottomonium states. We use the relativized quark model to calculate the masses and wavefunctions which are used to calculate the decay properties. The open bottom decay widths are calculated using the $^3P_0$ model. We also summarize results for radiative transitions, annihilation decays, hadronic transitions and production cross sections which are used to develop strategies to find these states. We find that the $b\\bar{b}$ system has a rich spectroscopy that we expect to be substantially extended by the LHC and $e^+e^-$ experiments in the near future. Some of the most promising possibilities at the LHC are observing the $\\chi_{b(1,2)}(3P)$, $\\chi_{b(1,2)}(4P)$ and $\\eta_b(3S)$ states in...
Leskovec, Luka [Stefan Inst., Ljubljana; Lang, C. B. [Graz U.; Mohler, Daniel [Fermilab; Prelovsek, Sasa [Stefan Inst., Ljubljana; Woloshyn, R. M. [TRIUMF
2015-11-12
We study the positive parity charmed strange mesons using lattice QCD, the only reliable ab initio method to study QCD at low energies. Especially the experimentally observed $D_{s0}^*(2317)$ and $D_{s1}(2460)$ have challenged theory for quite some time. The dynamical lattice QCD simulations are performed at two distinct pion masses, $m_{\\pi}$ = 266 MeV and 156 MeV, using both $\\bar{c}s$ as well as $DK$ and $D^*K$ scattering operators in the construction of the correlation matrix in order to take into the account threshold effects. While the $J^P = 0^+$ channel benefited most from the inclusion of scattering operators, it was also crucial for the case of the $D_{s1}(2460)$. Using the L\\"uscher method, which relates the finite volume spectrum to the infinite volume scattering matrix, we were able to determine the near threshold behavior of the scattering amplitude. From it we extracted the binding momenta and the masses of the below-threshold bound states $D_{s0}^*(2317)$ and $D_{s1}(2460)$ by determining the pole positions of the scattering amplitudes. Our results compare well with experiment, resolving a long standing discrepancy between theory and experiment.
Decoherence induced CPT violation and entangled neutral mesons
We discuss two classes of semimicroscopic theoretical models of stochastic spacetime foam in quantum gravity and the associated effects on entangled states of neutral mesons, signalling an intrinsic breakdown of CPT invariance. One class of models deals with a specific model of foam, initially constructed in the context of noncritical (Liouville) string theory, but viewed here in the more general context of effective quantum-gravity models. The relevant Hamiltonian perturbation, describing the interaction of the meson with the foam medium, consists of off-diagonal stochastic metric fluctuations, connecting distinct mass eigenstates (or the appropriate generalization thereof in the case of K-mesons), and it is proportional to the relevant momentum transfer (along the direction of motion of the meson pair). There are two kinds of CPT-violating effects in this case, which can be experimentally disentangled: one (termed 'ω-effect') is associated with the failure of the indistinguishability between the neutral meson and its antiparticle, and affects certain symmetry properties of the initial state of the two-meson system; the second effect is generated by the time evolution of the system in the medium of the spacetime foam, and can result in time-dependent contributions of the ω-effect type in the time profile of the two-meson state. Estimates of both effects are given, which show that, at least in certain models, such effects are not far from the sensitivity of experimental facilities available currently or in the near future. The other class of quantum-gravity models involves a medium of gravitational fluctuations which behaves like a 'thermal bath'. In this model both of the above-mentioned intrinsic CPT violation effects are not valid
Yukawa Meson, Sakata Model and Baryon-Lepton Symmetry Revisited
Marshak, R. E.
It is difficult for me to grasp that this symposium is celebrating the jubilee of meson theory since I was a junior at Columbia College in 1935. I recall hearing a colloquium by Paul Dirac that year telling an enraptured audience about the infinite sea of negative energy states but I do not recall any special note being taken of the birth of an equally revolutionary concept, the Yukawa meson. Perhaps the reason was the publication of Hideki Yukawa's paper in an inaccessible Japanese journal, perhaps Dirac's electron theory was dealing with the well-known electromagnetic force whereas Yukawa' meson theory was put forth to understand the nature of two new forces - the nuclear and the weak. Whatever the reason, the situation changed drastically when I migrated to Cornell (to do my thesis under Hans Bethe during the years 1937sim39) and found a deep interest in meson theory. Thus, my own scientific career has almost spanned the period since the birth of meson theory but, what is more to the point, it has been strongly influenced by the work of Yukawa and his collaborators. It therefore gives me great pleasure to be able to talk at this MESON 50 symposium. As one of the oldest speakers, I shall respond in a loose way to Professor Maki's invitation to cover ``topics concerning the historical developments of hadron physics''. I shall select several major themes from the Japanese work that have had special interest for me. My remarks will fall under the four headings: (A) Yukawa Meson; (B) Sakata Model; (C) Baryon-Lepton Symmetry; and (D) Extensions of Baryon-Lepton Symmetry.
A unitarized meson model including color Coulomb interaction
Ch. 1 gives a general introduction into the problem field of the thesis. It discusses in how far the internal structure of mesons is understood theoretically and which models exist. It discusses from a phenomenological point of view the problem of confinement indicates how quark models of mesons may provide insight in this phenomenon. In ch. 2 the formal theory of scattering in a system with confinement is given. It is shown how a coupled channel (CC) description and the work of other authors fit into this general framework. Explicit examples and arguments are given to support the CC treatment of such a system. In ch. 3 the full coupled-channel model as is employed in this thesis is presented. On the basis of arguments from the former chapters and the observed regularities in the experimental data, the choices underlying the model are supported. In this model confinement is described with a mass-dependent harmonic-oscillator potential and the presence of open (meson-meson) channels plays an essential role. In ch. 4 the unitarized model is applied to light scalar meson resonances. In this regime the contribution of the open channels is considerable. It is demonstrated that the model parameters as used for the description of the pseudo-scalar and vector mesons, unchanged can be used for the description of these mesons. Ch. 5 treats the color-Coulomb interaction. There the effect of the Coulomb interaction is studied in simple models without decay. The results of incorporating the color-Coulomb interaction into the full CC model are given in ch.6. Ch. 7 discusses the results of the previous chapters and the present status of the model. (author). 182 refs.; 16 figs.; 33 tabs
Study of light mesons with WASA-at-COSY
Prencipe Elisabetta
2014-06-01
Full Text Available The WASA detector, operating at the COSY facility in Jülich (Germany has been collecting data since 2007. The experiment allows to perform studies of light mesons, such as π0, η and ω rare decay processes, in order to perform precise measurements of branching ratios, determine Dalitz plot parameters, test symmetry and symmetry breaking, and evaluate transition form factors. In the experiments a proton or deuteron beam impinged on a pellet target of hydrogen or deuterium, which allows the reactions proton-proton (pp or proton-deuteron (pd. A high-statistics sample of η mesons has been collected: in the reaction pd →3He η, 3×107η mesons were tagged at a beam energy of 1.0 GeV, while 5×108η mesons were produced in the reaction pp → ppη at 1.4 GeV. This corresponds to the production of 10 η/s and 100 η/s, respectively, for the two reaction processes. In the pp dataset a higher background level is found compared to the pd data set. In both cases, we identify the η mesons by means of the missing mass derived from the recoil particles. A kinematic fit largely rejects the background in our analysis. The advantage in using the pp dataset is that the production of η mesons is almost a factor of 10 higher than in the pd fusion to 3He. As we plan to measure the branching ratios of very rare processes, high statistics is needed. A summary of the recent activity on the study of light mesons with WASA-at-COSY here is given.
Suppressed Decays of D_s^+ Mesons to Two Pseudoscalar Mesons
Adams, G S; Cummings, J P; Danko, I; Hu, D; Moziak, B; Napolitano, J; He, Q; Insler, J; Muramatsu, H; Park, C S; Thorndike, E H; Yang, F; Artuso, M; Blusk, S; Khalil, S; Li, J; Menaa, N; Mountain, R; Nisar, S; Randrianarivony, K; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Bonvicini, G; Cinabro, D; Dubrovin, M; Lincoln, A; Asner, D M; Edwards, K W; Naik, P; Briere, R A; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Cassel, D G; Duboscq, J E; Ehrlich, R; Fields, L; Gibbons, L; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Mohapatra, D; Onyisi, P U E; Patterson, J R; Peterson, D; Riley, D; Ryd, A; Sadoff, A J; Shi, X; Stroiney, S; Sun, W M; Wilksen, T; Athar, S B; Patel, R; Yelton, J; Rubin, P; Eisenstein, B I; Karliner, I; Lowrey, N; Selen, M; White, E J; Wiss, J; Mitchell, R E; Shepherd, M R; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Poling, R; Scott, A W; Zweber, P; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A G; Ernst, J; Ecklund, K M; Severini, H; Love, W; Savinov, V; López, A; Mehrabyan, S; Méndez, H; Ramírez, J; Ge, J Y; Miller, D H; Sanghi, B; Shipsey, I P J; Xin, B
2007-01-01
Using data collected near the Ds*+ Ds- peak production energy Ecm = 4170 MeV by the CLEO-c detector, we study the decays of Ds+ mesons to two pseudoscalar mesons. We report on searches for the singly-Cabibbo-suppressed Ds+ decay modes K+ eta, K+ eta', pi+ K0S, K+ pi0, and the isospin-forbidden decay mode Ds+ to pi+ pi0. We normalize with respect to the Cabibbo-favored Ds+ modes pi+ eta, pi+ eta', and K+ K0S, and obtain ratios of branching fractions: Ds+ to K+ eta / Ds+ to pi+ eta = (8.9 +- 1.5 +- 0.4)%, Ds+ to K+ eta' / Ds+ to pi+ eta' = (4.2 +- 1.3 +- 0.3)%, Ds+ to pi+ K0S / Ds+ to K+ K0S = (8.2 +- 0.9 +- 0.2)%, Ds+ to K+ pi0 / Ds+ to K+ K0S = (5.0 +- 1.2 +- 0.6)%, and Ds+ to pi+ pi0 / Ds+ to K+ K0S < 4.1% at 90% CL, where the uncertainties are statistical and systematic, respectively.
Relative rates of B meson decays into psi(2S) and J/psi mesons
Abazov, V M; Abolins, M; Acharya, B S; Adams, M; Adams, T; Aguiló, E; Ahn, S H; Ahsan, M; Alexeev, G D; Alkhazov, G; Alton, A; Alverson, G; Alves, G A; Anastasoaie, M; Ancu, L S; Andeen, T; Anderson, S; Andrieu, B; Anzelc, M S; Aoki, M; Arnoud, Y; Arov, M; Arthaud, M; Askew, A; sman, B; Assis-Jesus, A C S; Atramentov, O; Avila, C; Badaud, F; Baden, A A; Bagby, L; Baldin, B; Bandurin, D V; Banerjee, P; Banerjee, S; Barberis, E; Barfuss, A F; Bargassa, P; Baringer, P; Barreto, J; Bartlett, J F; Bassler, U; Bauer, D; Beale, S; Bean, A; Begalli, M; Begel, M; Belanger-Champagne, C; Bellantoni, L; Bellavance, A; Benítez, J A; Beri, S B; Bernardi, G; Bernhard, R; Bertram, I; Besanon, M; Beuselinck, R; Bezzubov, V A; Bhat, P C; Bhatnagar, V; Biscarat, C; Blazey, G; Blekman, F; Blessing, S; Bloch, D; Bloom, K; Böhnlein, A; Boline, D; Bolton, T A; Boos, E E; Borissov, G; Bose, T; Brandt, A; Brock, R; Brooijmans, G; Bross, A; Brown, D; Buchanan, N J; Buchholz, D; Bühler, M; Büscher, V; Bunichev, V; Burdin, S; Burke, S; Burnett, T H; Buszello, C P; Butler, J M; Calfayan, P; Calvet, S; Cammin, J; Carvalho, W; Casey, B C K; Castilla-Valdez, H; Chakrabarti, S; Chakraborty, D; Chan, K; Chan, K M; Chandra, A; Charles, F; Cheu, E; Chevallier, F; Cho, D K; Choi, S; Choudhary, B; Christofek, L; Christoudias, T; Cihangir, S; Claes, D; Clutter, J; Cooke, M; Cooper, W E; Corcoran, M; Couderc, F; Cousinou, M C; Crepe-Renaudin, S; Cutts, D; Cwiok, M; Da Motta, H; Das, A; Davies, G; De, K; De Jong, S J; De La Cruz-Burelo, E; De Oliveira Martins, C; Degenhardt, J D; Dliot, F; Demarteau, M; Demina, R; Denisov, D; Denisov, S P; Desai, S; Diehl, H T; Diesburg, M; Dominguez, A; Dong, H; Dudko, L V; Duflot, L; Dugad, S R; Duggan, D; Duperrin, A; Dyer, J; Dyshkant, A; Eads, M; Edmunds, D; Ellison, J; Elvira, V D; Enari, Y; Eno, S; Ermolov, P; Evans, H; Evdokimov, A; Evdokimov, V N; Ferapontov, A V; Ferbel, T; Fiedler, F; Filthaut, F; Fisher, W; Fisk, H E; Fortner, M; Fox, H; Fu, S; Fuess, S; Gadfort, T; Galea, C F; Gallas, E; García, C; García-Bellido, A; Gavrilov, V; Gay, P; Geist, W; Gel, D; Gerber, C E; Gershtein, Yu; Gillberg, D; Ginther, G; Gollub, N; Gmez, B; Goussiou, A; Grannis, P D; Greenlee, H; Greenwood, Z D; Gregores, E M; Grenier, G; Gris, P; Grivaz, J F; Grohsjean, A; Grünendahl, S; Grünewald, M W; Guo, F; Guo, J; Gutíerrez, G; Gutíerrez, P; Haas, A; Hadley, N J; Haefner, P; Hagopian, S; Haley, J; Hall, I; Hall, R E; Han, L; Harder, K; Harel, A; Hauptman, J M; Hauser, R; Hays, J; Hebbeker, T; Hedin, D; Hegeman, J G; Heinson, A P; Heintz, U; Hensel, C; Herner, K; Hesketh, G; Hildreth, M D; Hirosky, R; Hobbs, J D; Hoeneisen, B; Hoeth, H; Hohlfeld, M; Hong, S J; Hossain, S; Houben, P; Hu, Y; Hubacek, Z; Hynek, V; Iashvili, I; Illingworth, R; Ito, A S; Jabeen, S; Jaffré, M; Jain, S; Jakobs, K; Jarvis, C; Jesik, R; Johns, K; Johnson, C; Johnson, M; Jonckheere, A; Jonsson, P; Juste, A; Kajfasz, E; Kalk, J M; Karmanov, D; Kasper, P A; Katsanos, I; Kau, D; Kaushik, V; Kehoe, R; Kermiche, S; Khalatyan, N; Khanov, A; Kharchilava, A; Kharzheev, Yu M; Khatidze, D; Kim, T J; Kirby, M H; Kirsch, M; Klima, B; Kohli, J M; Konrath, J P; Kozelov, A V; Kraus, J; Krop, D; Kühl, T; Kumar, A; Kupco, A; Kura, T; Kuzmin, V A; Kvita, J; Lacroix, F; Lam, D; Lammers, S; Landsberg, G; Lebrun, P; Lee, W M; Leflat, A; Lellouch, J; Lévêque, J; Li, J; Li, L; Li, Q Z; Lietti, S M; Lima, J G R; Lincoln, D; Linnemann, J; Lipaev, V V; Lipton, R; Liu, Y; Liu, Z; Lobodenko, A; Lokajícek, M; Love, P; Lubatti, H J; Luna, R; Lyon, A L; Maciel, A K A; Mackin, D; Madaras, R J; Mättig, P; Magass, C; Magerkurth, A; Mal, P K; Malbouisson, H B; Malik, S; Malyshev, V L; Mao, H S; Maravin, Y; Martin, B; McCarthy, R; Melnitchouk, A; Mendoza, L; Mercadante, P G; Merkin, M; Merritt, K W; Meyer, A; Meyer, J; Millet, T; Mitrevski, J; Mommsen, R K; Mondal, N K; Moore, R W; Moulik, T; Muanza, G S; Mulhearn, M; Mundal, O; Mundim, L; Nagy, E; Naimuddin, M; Narain, M; Naumann, N A; Neal, H A; Negret, J P; Neustroev, P; Nilsen, H; Nogima, H; Novaes, S F; Nunnemann, T; O'Dell, V; O'Neil, D C; Obrant, G; Ochando, C; Onoprienko, D; Oshima, N; Osman, N; Osta, J; Otec, R; Oteroy Garzn, G J; Owen, M; Padley, P; Pangilinan, M; Parashar, N; Park, S J; Park, S K; Parsons, J; Partridge, R; Parua, N; Patwa, A; Pawloski, G; Penning, B; Perfilov, M; Peters, K; Peters, Y; Pétroff, P; Petteni, M; Piegaia, R; Piper, J; Pleier, M A; Podesta-Lerma, P L M; Podstavkov, V M; Pogorelov, Y; Pol, M E; Polozov, P; Pope, B G; Popov, A V; Potter, C; Prado da Silva, W L; Prosper, H B; Protopopescu, S; Qian, J; Quadt, A; Quinn, B; Rakitine, A; Rangel, M S; Ranjan, K; Ratoff, P N; Renkel, P; Reucroft, S; Rich, P; Rieger, J; Rijssenbeek, M; Ripp-Baudot, I; Rizatdinova, F; Robinson, S; Rodrigues, R F; Rominsky, M; Royon, C; Rubinov, P; Ruchti, R; Safronov, G; Sajot, G; Salzmann, C; Snchez-Hernndez, A; Sanders, M P; Sanghi, B; Santoro, A; Savage, G; Sawyer, L; Scanlon, T; Schaile, A D; Schamberger, R D; Scheglov, Y; Schellman, H; Schliephake, T; Schwanenberger, C; Schwartzman, A; Schwienhorst, R; Sekaric, J; Severini, H; Shabalina, E; Shamim, M; Shary, V; Shchukin, A A; Shivpuri, R K; Siccardi, V; Simák, V; Sirotenko, V; Skubic, P; Slattery, P; Smirnov, D; Snow, G R; Snow, J; Snyder, S; Söldner-Rembold, S; Sonnenschein, L; Sopczak, A; Sosebee, M; Soustruznik, K; Spurlock, B; Stark, J; Steele, J; Stolin, V; Stoyanova, D A; Strandberg, J; Strandberg, S; Strang, M A; Strauss, E; Strauss, M; Strhomer, R; Strom, D; Stutte, L; Sumowidagdo, S; Svoisky, P; Sznajder, A; Tamburello, P; Tanasijczuk, A; Taylor, W; Temple, J; Tiller, B; Tissandier, F; Titov, M; Tokmenin, V V; Toole, T; Torchiani, I; Trefzger, T; Tsybychev, D; Tuchming, B; Tully, C; Tuts, P M; Unalan, R; Uvarov, L; Uvarov, S; Uzunyan, S; Vachon, B; vanden Berg, P J; Van Kooten, R; Van Leeuwen, W M; Varelas, N; Varnes, E W; Vasilyev, I A; Vaupel, M; Verdier, P; Vertogradov, L S; Verzocchi, M; Villeneuve-Séguier, F; Vint, P; Vokac, P; Von Törne, E; Voutilainen, M; Wagner, R; Wahl, H D; Wang, L; Wang, M H L S; Warchol, J; Watts, G; Wayne, M; Weber, G; Weber, M; Welty-Rieger, L; Wenger, A; Wermes, N; Wetstein, M; White, A; Wicke, D; Wilson, G W; Wimpenny, S J; Wobisch, M; Wood, D R; Wyatt, T R; Xie, Y; Yacoob, S; Yamada, R; Yan, M; Yasuda, T; Yatsunenko, Y A; Yip, K; Yoo, H D; Youn, S W; Yu, J; Zeitnitz, C; Zhao, T; Zhou, B; Zhu, J; Zielinski, M; Zieminska, D; Zieminski, A; Zivkovic, L; Zutshi, V; Zverev, E G
2008-01-01
We report on a study of the relative rates of B meson decays into psi(2S) and J/psi mesons using 1.3 fb^-1 of pbar p collisions at sqrt(s) = 1.96 TeV recorded by the D0 detector operating at the Fermilab Tevatron Collider. We observe the channels B^0_s -> psi(2S)phi, B^0_s -> J/psi phi, B^+/- -> psi(2S) K^+/-, and B^+/- -> J/psi K^+/- and we measure the relative branching fractions for these channels to be B(B^0_s -> psi(2S)phi)/B(B^0_s -> J/psi phi) = 0.55 +/- 0.11 (stat) +/- 0.07 (syst) +/- 0.06 (B), B(B^+/- -> psi(2S) K^+/-)/B(B^+/- -> J/psi K^+/-) = 0.65 +/- 0.04 (stat) +/- 0.03 (syst) +/- 0.07 (B) where the final error corresponds to the uncertainty in the J/psi and psi(2S) branching ratio into two muons.
Molecular components in P-wave charmed-strange mesons
Ortega, Pablo G; Entem, David R; Fernandez, Francisco
2016-01-01
Results obtained by various experiments show that the $D_{s0}^{\\ast}(2317)$ and $D_{s1}(2460)$ mesons are very narrow states located below the $DK$ and $D^{\\ast}K$ thresholds, respectively. This is markedly in contrast with the expectations of naive quark models and heavy quark symmetry. Motivated by a recent lattice study which addresses the mass shifts of the $c\\bar{s}$ ground states with quantum numbers $J^{P}=0^{+}$ ($D_{s0}^{\\ast}(2317)$) and $J^{P}=1^{+}$ ($D_{s1}(2460)$) due to their coupling with $S$-wave $D^{(\\ast)}K$ thresholds, we perform a similar analysis within a nonrelativistic constituent quark model in which quark-antiquark and meson-meson degrees of freedom are incorporated. The quark model has been applied to a wide range of hadronic observables and thus the model parameters are completely constrained. The coupling between quark-antiquark and meson-meson Fock components is done using a modified version of the $^{3}P_{0}$ decay model. We observe that the coupling of the $0^{+}$ $(1^{+})$ mes...
DS Mesons in Asymmetric Hot and Dense Hadronic Matter
Divakar Pathak
2015-01-01
Full Text Available The in-medium properties of DS mesons are investigated within the framework of an effective hadronic model, which is a generalization of a chiral SU(3 model, to SU(4, in order to study the interactions of the charmed hadrons. In the present work, the DS mesons are observed to experience net attractive interactions in a dense hadronic medium, hence reducing the masses of the DS+ and DS- mesons from the vacuum values. While this conclusion holds in both nuclear and hyperonic media, the magnitude of the mass drop is observed to intensify with the inclusion of strangeness in the medium. Additionally, in hyperonic medium, the mass degeneracy of the DS mesons is observed to be broken, due to opposite signs of the Weinberg-Tomozawa interaction term in the Lagrangian density. Along with the magnitude of the mass drops, the mass splitting between DS+ and DS- mesons is also observed to grow with an increase in baryonic density and strangeness content of the medium. However, all medium effects analyzed are found to be weakly dependent on isospin asymmetry and temperature. We discuss the possible implications emanating from this analysis, which are all expected to make a significant difference to observables in heavy ion collision experiments, especially the upcoming Compressed Baryonic Matter (CBM experiment at the future Facility for Antiproton and Ion Research (FAIR, GSI, where matter at high baryonic densities is planned to be produced.
Rapidity resummation for B-meson wave functions
Shen Yue-Long
2014-01-01
Full Text Available Transverse-momentum dependent (TMD hadronic wave functions develop light-cone divergences under QCD corrections, which are commonly regularized by the rapidity ζ of gauge vector defining the non-light-like Wilson lines. The yielding rapidity logarithms from infrared enhancement need to be resummed for both hadronic wave functions and short-distance functions, to achieve scheme-independent calculations of physical quantities. We briefly review the recent progress on the rapidity resummation for B-meson wave functions which are the key ingredients of TMD factorization formulae for radiative-leptonic, semi-leptonic and non-leptonic B-meson decays. The crucial observation is that rapidity resummation induces a strong suppression of B-meson wave functions at small light-quark momentum, strengthening the applicability of TMD factorization in exclusive B-meson decays. The phenomenological consequence of rapidity-resummation improved B-meson wave functions is further discussed in the context of B → π transition form factors at large hadronic recoil.
Properties of strange vector mesons in dense and hot matter
We investigate the in-medium properties of strange vector mesons (K⁎ and K¯⁎) in dense and hot nuclear matter based on chirally motivated models of the meson self-energies. We parameterise medium effects as density or temperature dependent effective masses and widths, obtain the vector meson spectral functions within a Breit–Wigner prescription (as often used in transport simulations) and study whether such an approach can retain the essential features of full microscopic calculations. For μB≠0 the medium corrections arise from K¯⁎(K⁎)N scattering and the K¯⁎(K⁎)→K¯(K)π decay mode (accounting for in-medium K¯(K) dynamics). We calculate the scattering contribution to the K⁎ self-energy based on the hidden local symmetry formalism for vector meson nucleon interactions, whereas for the K¯⁎ self-energy we implement recent results from a self-consistent coupled-channel determination within the same approach. For μB≃0 and finite temperature we rely on a phenomenological approach for the kaon self-energy in a hot pionic medium consistent with chiral symmetry, and evaluate the K¯⁎(K⁎)→K¯(K)π decay width. The emergence of a mass shift at finite temperature is studied with a dispersion relation over the imaginary part of the vector meson self-energy
Interaction of vector mesons with baryons and nuclei
After some short introductory remarks on particular issues on the vector mesons in nuclei, in this paper, we present a short review of recent developments concerning the interaction of vector mesons with baryons and with nuclei from a modern perspective using the local hidden gauge formalism for the interaction of vector mesons. We present results for the vector–baryon interaction and in particular for the resonances which appear as composite states, dynamically generated from the interaction of vector mesons with baryons, taking also the mixing of these states with pseudoscalars and baryons into account. We then venture into the charm sector, reporting on hidden charm baryon states around 4400 MeV, generated from the interaction of vector mesons and baryons with charm, which have a strong repercussion on the properties of the J/ΨN interaction. We also address the interaction of K* with nuclei and make suggestions to measure the predicted huge width in the medium by means of transparency ratio. The formalism is extended to study the phenomenon of J/ψ suppression in nuclei via J/ψ photo-production reactions. (author)
The meson-baryon effective chiral Lagrangians at order $p^4$
Jiang, Shao-Zhou
2016-01-01
We construct the three-flavor Lorentz-invariant meson-baryon chiral Lagrangians at the order $p^4$. There exist 540 terms. The minimal numbers of mesons and photons related to these terms are also given.
Recollection of meson multiparticle production studies
More than fifty years have passed since the author started to study high energy physics theory in Tomonaga's group as a graduate student. At first the status of the meson multiparticle production theory before that time is summarized briefly mentioning the points of theories by (1) Lowis, Oppenheimer and Weuthusen (LOW), (2) Fukuda and Takeda, (3) Heisenberg, (4) Fermi and (5) Landau. Social background in Japan after the World War II is also realistically described. Landau's theory was very interesting as Koba suggested 'What Landau says will be necessarily proven to be true finally.' Then knowledge at that time from the cosmic ray is summarized i.e., the sharp angular distribution of the secondary particles, multiplicity, inelasticity and so on comparing them with the models of Fermi, Heisenberg, LOW and Landau. The nucleon to nuclei collision was studied based on Landau hydrodynamic model assuming the nuclei interact with the nucleus with the tube which the nucleon bores while penetrating a nucleus. Shock waves were solved to obtain energy and entropy distributions. The hydrodynamic model is then considered with the field theoretical view in mind. The limit of Landau model is discussed referring to the irreversible process by Kubo. The relation between elastic scattering and multiparticle production is discussed. Finally the quark cascade model including quark recombination is discussed. This model was invented to avoid the problem at the front part of the fluid which is not in local thermal equilibrium though needed to apply the hydrodynamic model. A new type of model was formulated for this part by using time dependent diffusion equation. (S. Funahashi)
Contribution of hadronic intermediate states in nonleptonic weak decays of K, charm and B mesons
We demonstrate that contributions of hadronic intermediate states are important in nonleptonic weak decays of K and charm mesons. Among various hadrons, exotic mesons can play an essential role in charm meson decays and also in the small violation of the so-called |ΔI| = 1/2 rule in K → ππ decays. The same technique is applied to B meson decays. (author)
Sun, Bao-Xi; Lu, Xiao-Fu; Shen, Peng-Nian; Zhao, En-Guang
2002-01-01
The Debye screening masses of the $\\sigma$, $\\omega$ and neutral $\\rho$ mesons and the photon are calculated in the relativistic mean-field approximation. As the density of the nucleon increases, all the screening masses of mesons increase. It shows a different result with Brown-Rho scaling, which implies a reduction in the mass of all the mesons in the nuclear matter except the pion. Replacing the masses of the mesons with their corresponding screening masses in Walecka-1 model, five saturat...
Effect of in-medium parameters of ρ meson in its photoproduction reactions on nuclei
There exist model calculations showing the modification of the hadronic parameters of ρ meson in the nuclear environment. From these parameters, we extract the ρ-meson-nucleus optical potential and show the medium effect due to this potential on the ρ-meson mass distribution spectra in the photonuclear reactions. The calculated results reproduced reasonably the measured e+e− invariant mass, i.e., ρ-meson mass, distribution spectra in γ, ρ0 → e+e− reactions on nuclei
Ishii, Masahiro; Yahiro, Masanobu
2016-01-01
We propose a practical effective model by introducing temperature ($T$) dependence to the coupling strengths of four-quark and six-quark Kobayashi-Maskawa-'t Hooft interactions in the 2+1 flavor Polyakov-loop extended Nambu-Jona-Lasinio model. The $T$ dependence is determined from LQCD data on the renormalized chiral condensate around the pseudocritical temperature $T_c^{\\chi}$ of chiral crossover and the screening-mass difference between $\\pi$ and $a_0$ mesons in $T > 1.1T_c^\\chi$ where only the $U(1)_{\\rm A}$-symmetry breaking survives. The model well reproduces LQCD data on screening masses $M_{\\xi}^{\\rm scr}(T)$ for both scalar and pseudoscalar mesons, particularly in $T \\ge T_c^{\\chi}$. Using this effective model, we predict meson pole masses $M_{\\xi}^{\\rm pole}(T)$ for scalar and pseudoscalar mesons. For $\\eta'$ meson, the prediction is consistent with the experimental value at finite $T$ measured in heavy-ion collisions. We point out that the relation $M_{\\xi}^{\\rm scr}(T)-M_{\\xi}^{\\rm pole}(T) \\approx...
Measurement of the Average $\\phi$ Multiplicity in $B$ Meson Decay
Aubert, Bernard; Boutigny, D; Gaillard, J M; Hicheur, A; Karyotakis, Yu; Lees, J P; Robbe, P; Tisserand, V; Zghiche, A; Palano, A; Pompili, A; Chen, J C; Qi, N D; Rong, G; Wang, P; Zhu, Y S; Eigen, G; Ofte, I; Stugu, B; Abrams, G S; Borgland, A W; Breon, A B; Brown, D N; Button-Shafer, J; Cahn, R N; Charles, E; Day, C T; Gill, M S; Gritsan, A V; Groysman, Y; Jacobsen, R G; Kadel, R W; Kadyk, J; Kerth, L T; Kolomensky, Yu G; Kukartsev, G; Le Clerc, C; Levi, M E; Lynch, G; Mir, L M; Oddone, P J; Orimoto, T J; Pripstein, M; Roe, N A; Romosan, A; Ronan, Michael T; Shelkov, V G; Telnov, A V; Wenzel, W A; Ford, K; Harrison, T J; Hawkes, C M; Knowles, D J; Morgan, S E; Penny, R C; Watson, A T; Watson, N K; Goetzen, K; Held, T; Koch, H; Lewandowski, B; Pelizaeus, M; Peters, K; Schmücker, H; Steinke, M; Boyd, J T; Chevalier, N; Cottingham, W N; Kelly, M P; Latham, T E; MacKay, C; Wilson, F F; Abe, K; Çuhadar-Dönszelmann, T; Hearty, C; Mattison, T S; McKenna, J A; Thiessen, D; Kyberd, P; McKemey, A K; Teodorescu, L; Blinov, V E; Bukin, A D; Golubev, V B; Ivanchenko, V N; Kravchenko, E A; Onuchin, A P; Serednyakov, S I; Skovpen, Yu I; Solodov, E P; Yushkov, A N; Best, D; Bruinsma, M; Chao, M; Kirkby, D; Lankford, A J; Mandelkern, M A; Mommsen, R K; Röthel, W; Stoker, D P; Buchanan, C; Hartfiel, B L; Gary, J W; Layter, J; Shen, B C; Wang, K; Del Re, D; Hadavand, H K; Hill, E J; MacFarlane, D B; Paar, H P; Rahatlou, S; Sharma, V; Berryhill, J W; Campagnari, C; Dahmes, B; Kuznetsova, N; Levy, S L; Long, O; Lu, A; Mazur, M A; Richman, J D; Rozen, Y; Verkerke, W; Beck, T W; Beringer, J; Eisner, A M; Heusch, C A; Lockman, W S; Schalk, T; Schmitz, R E; Schumm, B A; Seiden, A; Turri, M; Walkowiak, W; Williams, D C; Wilson, M G; Albert, J; Chen, E; Dubois-Felsmann, G P; Dvoretskii, A; Erwin, R J; Hitlin, D G; Narsky, I; Piatenko, T; Porter, F C; Ryd, A; Samuel, A; Yang, S; Jayatilleke, S M; Mancinelli, G; Meadows, B T; Sokoloff, M D; Abe, T; Blanc, F; Bloom, P; Chen, S; Clark, P J; Ford, W T; Nauenberg, U; Olivas, A; Rankin, P; Roy, J; Smith, J G; Van Hoek, W C; Zhang, L; Harton, J L; Hu, T; Soffer, A; Toki, W H; Wilson, R J; Zhang, J; Altenburg, D; Brandt, T; Brose, J; Colberg, T; Dickopp, M; Dubitzky, R S; Hauke, A; Lacker, H M; Maly, E; Müller-Pfefferkorn, R; Nogowski, R; Otto, S; Schubert, J; Schubert, Klaus R; Schwierz, R; Spaan, B; Wilden, L; Bernard, D; Bonneaud, G R; Brochard, F; Cohen-Tanugi, J; Grenier, P; Thiebaux, C; Vasileiadis, G; Verderi, M; Khan, A; Lavin, D; Muheim, F; Playfer, S; Swain, J E; Andreotti, M; Azzolini, V; Bettoni, D; Bozzi, C; Calabrese, R; Cibinetto, G; Luppi, E; Negrini, M; Piemontese, L; Sarti, A; Treadwell, E; Anulli, F; Baldini-Ferroli, R; Biasini, M; Calcaterra, A; De Sangro, R; Falciai, D; Finocchiaro, G; Patteri, P; Peruzzi, I M; Piccolo, M; Pioppi, M; Zallo, A; Buzzo, A; Capra, R; Contri, R; Crosetti, G; Lo Vetere, M; Macri, M; Monge, M R; Passaggio, S; Patrignani, C; Robutti, E; Santroni, A; Tosi, S; Bailey, S; Morii, M; Won, E; Bhimji, W; Bowerman, D A; Dauncey, P D; Egede, U; Eschrich, I; Gaillard, J R; Morton, G W; Nash, J A; Sanders, P; Taylor, G P; Grenier, G J; Lee, S J; Mallik, U; Cochran, J; Crawley, H B; Lamsa, J; Meyer, W T; Prell, S; Rosenberg, E I; Yi, J; Davier, M; Grosdidier, G; Höcker, A; Laplace, S; Le Diberder, F R; Lepeltier, V; Lutz, A M; Petersen, T C; Plaszczynski, S; Schune, M H; Tantot, L; Wormser, G; Brigljevic, V; Cheng, C H; Lange, D J; Simani, M C; Wright, D M; Bevan, A J; Coleman, J P; Fry, J R; Gabathuler, Erwin; Gamet, R; Kay, M; Parry, R J; Payne, D J; Sloane, R J; Touramanis, C; Back, J J; Cormack, C M; Harrison, P F; Shorthouse, H W; Vidal, P B; Brown, C L; Cowan, G; Flack, R L; Flächer, H U; George, S; Green, M G; Kurup, A; Marker, C E; McMahon, T R; Ricciardi, S; Salvatore, F; Vaitsas, G; Winter, M A; Brown, D; Davis, C L; Allison, J; Barlow, N R; Barlow, R J; Hart, P A; Hodgkinson, M C; Jackson, F; Lafferty, G D; Lyon, A J; Weatherall, J H; Williams, J C; Farbin, A; Jawahery, A; Kovalskyi, D; Lae, C K; Lillard, V; Roberts, D A; Blaylock, G; Dallapiccola, C; Flood, K T; Hertzbach, S S; Kofler, R; Koptchev, V B; Moore, T B; Saremi, S; Stängle, H; Willocq, S; Cowan, R; Sciolla, G; Taylor, F; Yamamoto, R K; Mangeol, D J J; Patel, P M; Robertson, S H; Lazzaro, A; Palombo, F; Bauer, J M; Cremaldi, L M; Eschenburg, V; Godang, R; Kroeger, R; Reidy, J; Sanders, D A; Summers, D J; Zhao, H W; Brunet, S; Cote-Ahern, D; Taras, P; Nicholson, H; Cartaro, C; Cavallo, N; De Nardo, Gallieno; Fabozzi, F; Gatto, C; Lista, L; Paolucci, P; Piccolo, D; Sciacca, C; Baak, M A; Raven, G; LoSecco, J M; Gabriel, T A; Brau, B; Gan, K K; Honscheid, K; Hufnagel, D; Kagan, H; Kass, R; Pulliam, T; Wong, Q K; Brau, J E; Frey, R; Potter, C T; Sinev, N B; Strom, D; Torrence, E; Colecchia, F; Dorigo, A; Galeazzi, F; Margoni, M; Morandin, M; Posocco, M; Rotondo, M; Simonetto, F; Stroili, R; Tiozzo, G; Voci, C; Benayoun, M; Briand, H; Chauveau, J; David, P; La Vaissière, C de; Del Buono, L; Hamon, O; John, M J J; Leruste, P; Ocariz, J; Pivk, M; Roos, L; Stark, J; T'Jampens, S; Therin, G; Manfredi, P F; Re, V; Behera, P K; Gladney, L; Guo, Q H; Panetta, J; Angelini, C; Batignani, G; Bettarini, S; Bondioli, M; Bucci, F; Calderini, G; Carpinelli, M; Del Gamba, V; Forti, F; Giorgi, M A; Lusiani, A; Marchiori, G; Martínez-Vidal, F; Morganti, M; Neri, N; Paoloni, E; Rama, M; Rizzo, G; Sandrelli, F; Walsh, J; Haire, M; Judd, D; Paick, K; Wagoner, D E; Danielson, N; Elmer, P; Lü, C; Miftakov, V; Olsen, J; Smith, A J S; Tanaka, H A; Varnes, E W; Bellini, F; Cavoto, G; Faccini, R; Ferrarotto, F; Ferroni, F; Gaspero, M; Mazzoni, M A; Morganti, S; Pierini, M; Piredda, G; Safai-Tehrani, F; Voena, C; Christ, S; Wagner, G; Waldi, R; Adye, T; De Groot, N; Franek, B J; Geddes, N I; Gopal, G P; Olaiya, E O; Xella, S M; Aleksan, Roy; Emery, S; Gaidot, A; Ganzhur, S F; Giraud, P F; Hamel de Monchenault, G; Monchenault; Kozanecki, Witold; Langer, M; Legendre, M; London, G W; Mayer, B; Schott, G; Vasseur, G; Yéche, C; Zito, M; Purohit, M V; Weidemann, A W; Yumiceva, F X; Aston, D; Bartoldus, R; Berger, N; Boyarski, A M; Buchmüller, O L; Convery, M R; Coupal, D P; Dong, D; Dorfan, J; Dujmic, D; Dunwoodie, W M; Field, R C; Glanzman, T; Gowdy, S J; Graugès-Pous, E; Hadig, T; Halyo, V; Hrynóva, T; Innes, W R; Jessop, C P; Kelsey, M H; Kim, P; Kocian, M L; Langenegger, U; Leith, D W G S; Libby, J; Luitz, S; Lüth, V; Lynch, H L; Marsiske, H; Messner, R; Müller, D R; O'Grady, C P; Ozcan, V E; Perazzo, A; Perl, M; Petrak, S; Ratcliff, B N; Roodman, A; Salnikov, A A; Schindler, R H; Schwiening, J; Simi, G; Snyder, A; Soha, A; Stelzer, J; Su, D; Sullivan, M K; Vavra, J; Wagner, S R; Weaver, M; Weinstein, A J R; Wisniewski, W J; Wright, D H; Young, C C; Burchat, Patricia R; Edwards, A J; Meyer, T I; Petersen, B A; Roat, C; Ahmed, M; Ahmed, S; Alam, M S; Ernst, J A; Saeed, M A; Saleem, M; Wappler, F R; Bugg, W; Krishnamurthy, M; Spanier, S M; Eckmann, R; Kim, H; Ritchie, J L; Schwitters, R F; Izen, J M; Kitayama, I; Lou, X C; Ye, S; Bianchi, F; Bóna, M; Gallo, F; Gamba, D; Borean, C; Bosisio, L; Della Ricca, G; Dittongo, S; Grancagnolo, S; Lanceri, L; Poropat, P; Vitale, L; Vuagnin, G; Panvini, R S; Banerjee, Sw; Brown, C M; Fortin, D; Jackson, P D; Kowalewski, R V; Roney, J M; Band, H R; Dasu, S; Datta, M; Eichenbaum, A M; Johnson, J R; Kutter, P E; Li, H; Liu, R; Di Lodovico, F; Mihályi, A; Mohapatra, A K; Pan, Y; Prepost, R; Sekula, S J; Von Wimmersperg-Töller, J H; Wu, J; Wu Sau Lan; Yu, Z; Neal, H
2003-01-01
We present a measurement of the average multiplicity of $\\phi$ mesons in $B^0$, $\\kern 0.18em\\bar{\\kern -0.18em B}{}^0$ and $B^\\pm$ meson decays. Using $17.6 fb^{-1}$ of data taken at the $\\Upsilon{(4S)}\\xspace$ resonance by the {\\slshape B\\kern-0.1em{\\smaller A}\\kern-0.1em B\\kern-0.1em{\\smaller A\\kern-0.2em R}} detector at the PEP-II $e^+e^-\\xspace$ storage ring at the Stanford Linear Accelerator Center, we reconstruct $\\phi$ mesons in the $K^+K^-$ decay mode and measure ${\\cal{B}}(B\\to \\phi X) = (3.41\\pm0.06\\pm0.12)%$. This is significantly more precise than any previous measurement.
Importance of Non-Perturbative QCD Parameters for Bottom Mesons
Upadhyay, A
2015-01-01
The importance of non-perturbative Quantum Chromodynamics [QCD] parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two non perturbative QCD parameters used in heavy quark effective theory formula and using the best fitted parameter, masses of the excited bottom meson states in JP=(1/2)+ doublet in strange as well as non-strange sector are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass and hyperfine splitting has also been analyzed for both strange and non-strange heavy mesons with respect to spin and flavor symmetries.
Charmed mesons and leptons from semileptonic decays at the LHC
Maciula, Rafal
2013-01-01
We discuss production of charmed mesons as well as electrons/muons from semileptonic decays of charm and bottom mesons in proton-proton collisions at the LHC. The cross section for inclusive production of $c \\bar c$ and $b \\bar b$ pairs is calculated in the framework of the $k_{\\perp}$-factorization approach. Here, the KMR and Jung CCFM unintegrated gluon distribution functions are used. Theoretical uncertainties of the model related to the choice of renormalization and factorization scales as well as due to the quark mass are also discussed. The hadronization of charm and bottom quarks is included within the fragmentation functions technique. Inclusive differential distributions in transverse momentum of charmed mesons are presented and compared to recent results of the ALICE collaboration. Furthermore, we also consider production of different $D \\bar D$ pairs in unique kinematics of forward rapidities of the LHCb experiment. Kinematical correlations in azimuthal angle $\\varphi_{D\\bar D}$ and invariant mass ...
Importance of Nonperturbative QCD Parameters for Bottom Mesons
The importance of nonperturbative quantum chromodynamics (QCD) parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=(1/2)+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries
Improved model of vector mesons in holographic QCD
We analyze the sector of dimension-three vector meson operators in the 'hard-wall' model of holographic QCD, including the vector and axial currents, dual to gauge fields in the bulk, and the tensor operator ψσμνψ, dual to a two-form field satisfying a complex self-duality condition. The model includes the effect of chiral symmetry breaking on vector mesons, that involves a coupling between the dual gauge field and the two-form field. We compute the leading logarithmic terms in the operator product expansion of two-point functions and the leading nonperturbative contribution to the tensor-vector correlator. The result is consistent with the operator product expansion of QCD. We also study the spectrum of vector mesons numerically.
Mesonic Decay of Charm Hypernuclei Λc+
Ghosh Sabyasachi
2016-01-01
Full Text Available Λc+ hypernuclei are expected to have binding energies and other properties similar to those of strange hypernuclei in view of the similarity between the quark structures of the strange and charmed hyperons, namely Λ(uds and Λc+(udc. One striking difference however occurs in their mesonic decays, as there is almost no Pauli blocking in the nucleonic decay of a charm hypernucleus because the final-state nucleons leave the nucleus at high energies. The nuclear medium nevertheless affects the mesonic decays of charm hypernucleus because the nuclear mean fields modify the masses of the charm hyperon. In the present communication we present results of a first investigation of the effects of finite baryon density on different weak mesonic decay channels of the Λc+ baryon. We found a non-negligible reduction of the decay widths as compared to their vacuum values.
Measurement of the B+ and B0 meson lifetimes
The lifetimes of the B+ and B0 mesons have been measured using fully reconstructed decays. In a sample of ∼49 600J/ψ→μ+μ- decays recorded with the Collider Detector at Fermilab, 148±16 B+ and 121±16B0 mesons have been reconstructed using the silicon vertex detector. Unbinned likelihood fits to the proper lifetime distributions of these B mesons give τ+=1.61±0.16 (stat)±0.05 (syst) ps, τ0=1.57±0.18 (stat) ±0.08 (syst) ps, and τ+/τ0=1.02±0.16 (stat) ±0.05 (syst)
Current status of high energy nucleon-meson transport code
Takada, Hiroshi; Sasa, Toshinobu [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment
1998-03-01
Current status of design code of accelerator (NMTC/JAERI code), outline of physical model and evaluation of accuracy of code were reported. To evaluate the nuclear performance of accelerator and strong spallation neutron origin, the nuclear reaction between high energy proton and target nuclide and behaviors of various produced particles are necessary. The nuclear design of spallation neutron system used a calculation code system connected the high energy nucleon{center_dot}meson transport code and the neutron{center_dot}photon transport code. NMTC/JAERI is described by the particle evaporation process under consideration of competition reaction of intranuclear cascade and fission process. Particle transport calculation was carried out for proton, neutron, {pi}- and {mu}-meson. To verify and improve accuracy of high energy nucleon-meson transport code, data of spallation and spallation neutron fragment by the integral experiment were collected. (S.Y.)
High statistics inclusive phi-meson production at SPS energies
This thesis describes an experiment studying the inclusive reaction hadron + Be → phi + anything → K+ + K- + anything in 100 GeV/c, 120 GeV/c and 200 GeV/c hadron interactions. A total of 8x106 events were recorded using both positively and negatively charged unseparated hadron beams supplied by the CERN SPS. The experiment made use of an intelligent on-line event selection system based on micro-processors (FAMPs) in conjunction with a system of large MWPCs to increase the number of phi-events recorded per unit time. In 32 days of data taking over 600,000 phi-mesons were recorded onto magnetic tape. The physics motivation for collecting a large statistics sample of inclusive phi-mesons was the investigation of the inclusive phi-meson production mechanism and phi-spectroscopy. (Auth.)
Evidence for Magnetic Fields in Light Meson Spectra
Akers, D
2003-01-01
Mac Gregor's constituent-quark model is reviewed with currently published data from light meson spectra. It was previously shown that magnetic sources were responsible for the quantization of several mass-splittings in Mac Gregor's model. The existence of a 70-MeV quantum was postulated by Mac Gregor and was shown to fit the Nambu empirical mass formula mn = (n/2)137me, n a positive integer. It is shown in this paper that the light meson spectra also fit into the constituent-quark model and are in agreement with the Russell-Saunders coupling scheme. The existence of magnetic fields is suggested by the successful accounting of these meson spectra.
Forward coherent $\\phi$-meson photoproduction from deuterons near threshold
Chang, W C; Ahn, J K; Akimune, H; Asano, Y; Daté, S; Ejiri, H; Fujimura, H; Fujiwara, M; Fukui, S; Hasegawa, S; Hicks, K; Horie, K; Hotta, T; Imai, K; Ishikawa, T; Iwata, T; Kato, Y; Kawai, H; Kim, Z Y; Kino, K; Kohri, H; Kumagai, N; Lin, P J; Makino, S; Matsuda, T; Matsumura, T; Matsuoka, N; Mibe, T; Miyabe, M; Miyachi, Y; Morita, M; Muramatsu, N; Nakano, T; Niiyama, M; Nomachi, M; Ohashi, Y; Ohkuma, H; Ooba, T; Oshuev, D S; Rangacharyulu, C; Sakaguchi, A; Sasaki, T; Shagin, P M; Shiino, Y; Shimizu, A; Shimizu, H; Shimizu, S; Sugaya, Y; Sumihama, M; Toi, Y; Toyokawa, H; Wakai, A; Wang, C W; Wang, S C; Yonehara, K; Yorita, T; Yoshimura, M; Yosoi, M; Zegers, R G T
2008-01-01
Differential cross sections and decay asymmetries for coherent $\\phi$-meson photoproduction from deuterons were measured for the first time at forward angles by linearly polarized photons at $E_{\\gamma}$= 1.5-2.4 GeV. With the elimination of isovector unnatural-parity $\\pi$-meson exchange in the interaction with isoscalar deuteron target, this reaction is expected to explore natural-parity Pomeron dynamics at low energies. Our measurements show that the cross sections at zero degrees increase steadily with photon energy and the decay asymmetries demonstrate a complete dominance of natural-parity exchange processes. Nevertheless the deduced cross sections of $\\phi$-mesons from nucleons contributed by isoscalar t-channel exchange processes are mostly underpredicted by conventional Pomeron model.
Proposal for the systematic naming of mesons and baryons
Twenty years ago, the Particle Data Group adopted a systematic naming convention for baryons: the symbols N, Δ, Λ, Σ, Ψ, and Ω were to identify the isospin and strangeness, The mesons, by contrast, have become an alphabet soup of uninformative names - theta, iota, xi, zeta, g/sub T/, g/sub s/, H, E, delta, h, g, r, kappa, etc. -, and in some cases identical names are used for mesons with different quantum numbers (A, B, and D). Furthermore, experimentalists are now discovering baryons that contain heavy quarks. It is therefore timely to consider systematic naming conventions both for mesons and for baryons with heavy quarks. The Particle Data Group is circulating this proposal in the hope of generating feedback, and we attach a sheet for responses. It should be emphasized that the Particle Tables would show both the old and new names for some time
Masses and decay widths of radially excited Bottom mesons
Gupta, Pallavi
2016-01-01
Inspired from the experimental information coming from LHC [2,3] and Babar [4] for radially higher excited charmed mesons, we predict the masses and decays of the n=2 S-wave and P- wave bottom mesons using the effective lagrangian approach. Using heavy quark effective theory approach, non-perturbative parameters (?, ?1 and ?2) are fitted using the available experimental and theoretical informations on charm masses. Using heavy quark symmetry and the values of these fitted parameters, the masses of radially excited even and odd parity bottom mesons with and without strangness are predicted. These predicted masses led in constraining the decay widths of these 12 states, and also shed light on the unknown values of the higher hadronic coupling constants eeg 2 SH and eeg 2 TH. Studying the properties like masses, decays of 2S and 2P states and some hadronic couplings would help forthcoming experiments to look into these states in future.
Effects of isovector scalar $\\delta$-meson on hypernuclei
Ikram, M; Biswal, S K; Patra, S K
2014-01-01
We analyze the effects of $\\delta-$ meson on hypernuclei within the frame-work of relativistic mean field theory. The $\\delta-$ meson is included into the Lagrangian for hypernuclei. The extra nucleon-meson coupling ($g_\\delta$) affects the every piece of physical observables, like binding energy, radii and single particle energy of hypernuclei. The lambda mean field potential is investigated which is consistent with other predictions. Flipping of single particle energy levels are observed with the strength of $g_\\delta$ in the considered hypernuclei as well as normal nuclei. The spin-orbit potentials are observed for considered hypernuclei and the effect of $g_\\delta$ on spin-orbit potentials is also analyzed. The calculated single-$\\Lambda$ binding energies ($B_\\Lambda$) are quite agreeable with the experimental data.
Importance of Nonperturbative QCD Parameters for Bottom Mesons
A. Upadhyay
2014-01-01
Full Text Available The importance of nonperturbative quantum chromodynamics (QCD parameters is discussed in context to the predicting power for bottom meson masses and isospin splitting. In the framework of heavy quark effective theory, the work presented here focuses on the different allowed values of the two nonperturbative QCD parameters used in heavy quark effective theory formula, and using the best fitted parameter, masses of the excited bottom meson states in jp=1/2+ doublet in strange and nonstrange sectors are calculated here. The calculated masses are found to be matching well with experiments and other phenomenological models. The mass splitting and hyperfine splitting have also been analyzed for both strange and nonstrange heavy mesons with respect to spin and flavor symmetries.
Hadronic molecules with a D ¯ meson in a medium
Caramés, T. F.; Fontoura, C. E.; Krein, G.; Tsushima, K.; Vijande, J.; Valcarce, A.
2016-08-01
We study the effect of a hot and dense medium on the binding energy of hadronic molecules with open-charm mesons. We focus on a recent chiral quark-model-based prediction of a molecular state in the N D ¯ system. We analyze how the two-body thresholds and the hadron-hadron interactions are modified when quark and meson masses and quark-meson couplings change in a function of the temperature and baryon density according to predictions of the Nambu-Jona-Lasinio model. We find that in some cases the molecular binding is enhanced in medium as compared to their free-space binding. We discuss the consequences of our findings for the search for exotic hadrons in high-energy heavy-ion collisions as well as in the forthcoming facilities FAIR or J-PARC.
Distribution amplitudes of light-quark mesons from lattice QCD
Segovia, Jorge; Cloet, Ian C; Roberts, Craig D; Schmidt, Sebastian M; Zong, Hong-shi
2013-01-01
We exploit a method introduced recently to determine parton distribution amplitudes (PDAs) from minimal information in order to obtain light-quark pseudoscalar and vector meson PDAs from the limited number of moments produced by numerical simulations of lattice-regularised QCD. Within errors, the PDAs of pseudoscalar and vector mesons constituted from the same valence quarks are identical; they are concave functions, whose dilation expresses the strength of dynamical chiral symmetry breaking; and SU(3)-flavour symmetry is broken nonperturbatively at the level of 10%. Notably, the appearance of precision in the lattice moments is misleading. The moments also exhibit material dependence on lattice volume, especially for the pion. Improvements need therefore be made before an accurate, unified picture of the light-front structure of light-quark pseudoscalar and vector mesons is revealed.
Radiative meson decays in a relativistic quark model
Motivated by the recent lattice QCD results indicating that the topological charge contribution to the flavor singlet axial vector current can be traded off by the constituent quark masses, we investigate the radiative decays of pseudoscalar (π, K, η, η'), vector (ρ, K*, ω, φ) and axial vector (A1) mesons using a simple relativistic constituent quark model. For both simplicity and relativity, we take advantage of the distinguished features in the light-cone quantization method: (1) the Fock-state expansion of meson wavefunctions are not contaminated by the vacuum fluctuation, (2) the assignment of meson quantum numbers are given by the Melosh transformation. The computed decay widths of ρ, ω → π(η)γ, K* → Kγ, A1 → πγ and the transition form factor of π0 → γ*γ at 0 ≤ Q2 ≤ 8 GeV2 are in a remarkably good agreement with the experimental data. (author)
Scalar mesons above and below 1 GeV
Close, Francis Edwin; Close, Frank E; Tornqvist, Nils A.
2002-01-01
We show that two nonets and a glueball provide a consistent description of data on scalar mesons below 1.7 GeV. Above 1 GeV the states form a conventional (q bar q) nonet mixed with the glueball of lattice QCD. Below 1 GeV the states also form a nonet, as implied by the attractive forces of QCD, but of more complicated nature. Near the center they are 4 quark states of the Jaffe type in S-wave, with some (q bar q) in P-wave, but further out they rearrange in colour to two colourless (q bar q) pairs and finally as meson-meson states. A simple effective chiral model for such a system with two scalar nonets can be made involving two coupled linear sigma models. One of these could be looked upon as the Higgs sector of nonpertubative QCD.
Incoherent photoproduction of pseudoscalar mesons off nuclei at forward angles
Gevorkyan, S; Gan, L; Larin, I; Khandaker, M
2009-01-01
Recent advances in the photon tagging facilities together with the novel, high resolution fast calorimetry made possible to perform photoproduction cross section measurements of pseudoscalar mesons on nuclei with a percent level accuracy. The extraction of the radiative decay widths, needed for testing the symmetry breaking effects in QCD, from these measurements at small angles is done by the Primakoff method. This method requires theoretical treatment of all processes participating in these reactions at the same percent level. The most updated description of general processes, including the nuclear coherent amplitude, is done in our previous paper. In this work, based on the framework of Glauber multiple scattering theory, we obtain analytical expressions for the incoherent cross section of the photoproduction of pseudoscalar mesons off nuclei accounting for the mesons absorption in nuclei and Pauli suppression at forward production angles. As illustrations of the obtained formulas, we calculate the incoher...
Regarding the enigmas of P-wave meson spectroscopy
The mass spectrum of P-wave mesons is considered in a nonrelativistic constituent quark model. The results show the common mass degeneracy of the isovector and isodoublet states of the scalar and tensor meson nonets, m(a0)congruent m(a2), m(K0*)congruent m(K2*), and do not exclude the possibility of a similar degeneracy of the same states of the axial-vector and pseudovector nonets. Current experimental hadronic and τ-decay data suggest, however, a different scenario leading to the a1 meson mass ≅1190 MeV and the K1A-K1B mixing angle ≅(37±3)degree. Possible s bar s states of the four nonets are also discussed. copyright 1998 The American Physical Society
On the spectra of scalar mesons from HQCD models
Mintakevich, Oded; Sonnenschein, Jacob
2008-08-01
We determine the holographic spectra of scalar mesons from the fluctuations of the embedding of flavor D-brane probes in HQCD models. The models we consider include a generalization of the Sakai Sugimoto model at zero temperature and at the ``high-temperature intermediate phase", where the system is in a deconfining phase while admitting chiral symmetry breaking and a non-critical 6d model at zero temperature. All these models are based on backgrounds associated with near extremal Nc D4 branes and a set of Nf mcq and on the excitation number n as Mn2 ~ mcq and M2n ~ n1.7 for the ten dimensional case and as Mn ~ mcq and Mn ~ n0.75 in the non-critical case. At the high temperature intermediate phase we detect a decrease of the masses of low spin mesons as a function of the temperature similar to holographic vector mesons and to lattice calculations.
Semileptonic Decays of Pseudoscalar Mesons: A New Approach
Chia, Swee Ping
2013-01-01
Because quarks in hadronic states are subjected to strong QCD forces, it is not straight-forward to apply calculation obtained at the quark level to physical processes involving hadrons. In this paper we present a new approach to treat the semileptonic decays of pseudoscalar mesons. At the quark level, the process is straightforward. However, when we fold the quark-level process to the meson decay process, the complication from QCD effects come in. We make the fundamental assumption that the vertex of type M-q-qbar can be approximated by an effective constant gamma-5 coupling. With this assumption, the hadronic process can then be related to the quark-level process. The model is applied to the semileptonic decays of pi, K, D and B mesons.
Scalar mesons above and below 1 GeV
We show that two nonets and a glueball provide a consistent description of data on scalar mesons below 1.7 GeV. Above 1 GeV the states form a conventional qq-bar nonet mixed with the glueball of lattice QCD. Below 1 GeV the states also form a nonet, as implied by the attractive forces of QCD, but of a more complicated nature. Near the centre they are (qq)3-bar(q-barq-bar)3 in S-wave, with some qq-bar in P-wave, but further out they rearrange as (qq-bar)1(qq-bar)1 and finally as meson-meson states. A simple effective chiral model for such a system with two scalar nonets can be made involving two coupled linear sigma models. One of these could be looked upon as the Higgs sector of nonpertubative QCD. (author)
Baryon and meson phenomenology in the extended Linear Sigma Model
The vacuum phenomenology obtained within the so-called extended Linear Sigma Model (eLSM) is presented. The eLSM Lagrangian is constructed by including from the very beginning vector and axial-vector d.o.f., and by requiring dilatation invariance and chiral symmetry. After a general introduction of the approach, particular attention is devoted to the latest results. In the mesonic sector the strong decays of the scalar and the pseudoscalar glueballs, the weak decays of the tau lepton into vector and axial-vector mesons, and the description of masses and decays of charmed mesons are shown. In the baryonic sector the omega production in proton-proton scattering and the inclusion of baryons with strangeness are described.
Mesonic Decay of Charm Hypernuclei Λc+
Ghosh, Sabyasachi; Fontoura, Carlos E.; Krein, Gastão
2016-03-01
Λc+ hypernuclei are expected to have binding energies and other properties similar to those of strange hypernuclei in view of the similarity between the quark structures of the strange and charmed hyperons, namely Λ(uds) and Λc+(udc). One striking difference however occurs in their mesonic decays, as there is almost no Pauli blocking in the nucleonic decay of a charm hypernucleus because the final-state nucleons leave the nucleus at high energies. The nuclear medium nevertheless affects the mesonic decays of charm hypernucleus because the nuclear mean fields modify the masses of the charm hyperon. In the present communication we present results of a first investigation of the effects of finite baryon density on different weak mesonic decay channels of the Λc+ baryon. We found a non-negligible reduction of the decay widths as compared to their vacuum values.
Mesonic Decay of Charm Hypernuclei $\\Lambda^+_c$
Ghosh, Sabyasachi; Krein, Gastão
2016-01-01
$\\Lambda^+_c$ hypernuclei are expected to have binding energies and other properties similar to those of strange hypernuclei in view of the similarity between the quark structures of the strange and charmed hyperons, namely $\\Lambda(uds)$ and $\\Lambda^+_c (udc)$. One striking difference however occurs in their mesonic decays, as there is almost no Pauli blocking in the nucleonic decay of a charm hypernucleus because the final-state nucleons leave the nucleus at high energies. The nuclear medium nevertheless affects the mesonic decays of charm hypernucleus because the nuclear mean fields modify the masses of the charm hyperon. In the present communication we present results of a first investigation of the effects of finite baryon density on different weak mesonic decay channels of the $\\Lambda^+_c$ baryon. We found a non-negligible reduction of the decay widths as compared to their vacuum values.
Observation of a New Narrow Axial-Vector Meson alpha(1)(1420)
Adolph, C.; Akhunzyanov, R.; Alexeev, M.; Alexeev, G. D.; Amoroso, A.; Andrieux, V.; Anosov, V.; Austregesilo, A.; Azevedo, C.; Badelek, B.; Balestra, F.; Barth, J.; Beck, R.; Bedfer, Y.; Bernhard, J.; Bicker, K.; Bielert, E. R.; Birsa, R.; Bisplinghoff, J.; Bodlák, M.; Boer, M.; Bordalo, P.; Bradamante, F.; Braun, C.; Bressan, A.; Büchele, M.; Burtin, E.; Chang, W.-C.; Chiosso, M.; Choi, I.; Chung, S. U.; Cicuttin, A.; Crespo, M.; Curiel, Q.; Dalla Torre, S.; Dasgupta, S. S.; Dasgupta, S.; Denisov, O.; Dhara, L.; Donskov, S. V.; Doshita, N.; Duic, V.; Dunnweber, W.; Dziewiecki, M.; Efremov, A.; Eversheim, P.D.; Eyrich, W.; Faessler, M.; Ferrero, A.; Finger, M.; Finger jr., M.; Fischer, H.; Franco, C.; Fresne von Hohenesche, N.; Friedrich, J. M.; Frolov, V.; Gautheron, F.; Gavrichtchouk, O. P.; Gerassimov, S.; Gnesi, I.; Gorzellik, M.; Grabmüller, S.; Grasso, A.; Grosse-Perdekapm, M.; Grube, B.; Grussenmeyer, T.; Guskov, A.; Haas, F.; von Harrach, D.; Hahne, D.; Hashimoto, R.; Heinsius, F. H.; Herrmann, E.; Hinterberger, F.; Horikawa, N.; d´Hose, N.; Hsieh, C.-Yu.; Huber, S.; Ishimoto, S.; Ivanov, A.; Ivanshin, Yu.; Iwata, T.; Jahn, R.; Jarý, V.; Jörg, P.; Joosten, R.; Kabuss, E.; Ketzer, B.; Khaustov, G. V.; Khokhlov, Yu. A.; Kisselev, Y.; Klein, F.; Klimaszewski, K.; Koivuniemi, J. H.; Kolosov, V. N.; Kondo, K.; Königsmann, K.; Konorov, I.; Konstantinov, V. F.; Kotzinian, A. M.; Kouznetsov, O.; Krämer, M.; Kremser, P.; Krinner, F.; Kroumchtein, Z. V.; Kuchinski, N.; Kunne, F.; Kurek, K.; Kurjata, R. P.; Lednev, A. A.; Lehmann, A.; Levillain, M.; Levorato, S.; Lichtenstadt, J.; Maggiora, A.; Magnon, A.; Makins, N.; Makke, N.; Mallot, G.; Marchand, C.; Martin, A.; Marzec, J.; Matoušek, J.; Matsuda, H.; Matsuda, T.; Meshcheryakov, G.; Meyer, W.; Michigami, T.; Mikhailov, Yu. V.; Miyachi, Y.; Nagaytsev, A.; Nagel, T.; Nerling, F.; Neyret, D.; Nikolaenko, V. I.; Nový, J.; Nowak, W. D.; Nunes, A.S.; Olshevsky, A. G.; Orlov, I.; Ostrick, M.; Panzieri, D.; Parsamyan, B.; Paul, S.; Peng, J.-C.; Pereira, F.; Pešek, M.; Peshekhonov, D. V.; Platchkov, S.; Pochodzalla, J.; Polyakov, V.; Pretz, J.; Quaresma, M.; Quintans, C.; Ramos, S.; Regali, C.; Reicherz, G.; Riedl, C.; Rocco, E.; Rossiyskaya, N. S.; Ryabchikov, D.; Rychter, A.; Samoylenko, V. D.; Sandacz, A.; Santos, C.; Sarkar, S.; Savin, I. A.; Sbrizzai, G.; Schiavon, P.; Schmeing, S.; Schmidt, K.; Schlüter, T.; Selyunin, A.; Schmieden, H.; Schönning, K.; Schopferer, S.; Shevchenko, O. Yu.; Silva, L.; Sinha, L.; Sirtl, S.; Slunecka, M.; Sozzi, F.; Srnka, Aleš; Stolarski, M.; Šulc, M.; Suzuki, H.; Szabelski, A.; Szameitat, T.; Sznajder, P.; Takekawa, S.; Ter Wolbeek, J.; Tessaro, S.; Tessarotto, F.; Thibaud, F.; Tskhay, V.; Uhl, S.; Veloso, J.; Virius, M.; Wallner, S.; Weisrock, T.; Wilfert, M.; Zaremba, K.; Zavertyaev, M.; Zemlyanichkina, E.; Ziembicki, M.; Zink, A.
2015-01-01
Roč. 115, č. 8 (2015), 082001:1-6. ISSN 0031-9007 R&D Projects: GA MŠk(CZ) LO1212 Institutional support: RVO:68081731 Keywords : COMPASS * pion-nucleon scattering * hadron spectroscopy * light-meson spectrum * axial-vector mesons * exotic mesons Subject RIV: BH - Optics, Masers, Lasers Impact factor: 7.512, year: 2014
Production of mesons with any internal orbital angular momentum in exclusive hard processes
Ichola, A.; Houra-Yaou, L.; Kessler, P.; Parisi, J. [College de France, 75 - Paris (France). Lab. de Physique Corpusculaire
1994-12-31
In this paper we present an extension of the computation of exclusive hard processes to the production of (qq) mesons with any orbital angular momentum, as well as of (gg) mesons (``glueballs``). We explicitly compute two examples: tensor-meson par production and glueball plus pion production, both in {gamma} {gamma} collisions. (authors). 16 refs., 7 figs., 1 tab.
Multiple production of π0 and eta mesons in soft hadronic processes
Inclusive spectra of π0 and eta mesons are calculated in the framework of a dual approach taking into account the two-sheet structure of the topological Pomeron. The results of a recent experiment on multiple production of π0 and eta mesons in a beam of 360-GeV π- mesons are analyzed
Exclusive and inclusive weak decays of the B-meson
Grach, I.L.; Narodetskii, I.M.; Ter-Martirosyan, K.A. [Institute of Theor. and Exp. Phys., Moscow (Russian Federation); Simula, S. [Istituto Nazionale di Fisica Nucleare, Sezione Sanita, Viale Regina Elena 299, I-00161 Rome (Italy)
1997-09-29
A relativistic quark model is applied to the description of semileptonic and non-leptonic charmed decays of the B-meson. The exclusive semileptonic modes B{yields}Dl{nu}{sub l} and B{yields}D{sup *}l{nu}{sub l} are described through the universal Isgur-Wise form factor, which is calculated in terms of a constituent quark model wave function for the B-meson. Different approximations for the latter, either based on a phenomenological ansatz or derived from analyses of the meson spectra, are adopted. In particular, two wave functions, constructed via the Hamiltonian light-front formalism using a relativized and a non-relativistic constituent quark model, are considered, obtaining a link between standard spectroscopic quark models and the B-meson decay physics. The inclusive semileptonic and non-leptonic branching ratios are calculated within a convolution approach, inspired by the partonic model and involving the same B-meson wave function used for the evaluation of the exclusive semileptonic modes. Our results for the major branching ratios are consistent with available experimental data and the sum of all the calculated branchingratios turns out to be close to unity. In particular, we found that (i) a remarkable fraction ({proportional_to}35%) of semileptonic decay modes occur in non-D, non-D{sup *} final states; (ii) non-perturbative effects enhance the inclusive b{yields}c anti ud decay channels, with a sizable contribution provided by internal decays into heavy mesons and baryon-antibaryon pairs; the resulting reduction of the semileptonic branching ratio brings the theoretical prediction in agreement with the experimental value without increasing at the same time the charm counting. (orig.). 47 refs.
Lattice results for low moments of light meson distribution amplitudes
As part of the UKQCD and RBC collaborations' Nf = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons π and K and the (longitudinally-polarised) vector mesons ρ, K* and φ. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI'/MOM technique. (orig.)
Lattice Results for Low Moments of Light Meson Distribution Amplitudes
Arthur, R; Brommel, D; Donnellan, M A; Flynn, J M; Juttner, A; Rae, T D; Sachrajda, C T.C
2011-01-01
As part of the UKQCD and RBC collaborations' N_f=2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons pion and kaon and the (longitudinally-polarised) vector mesons rho, K-star and phi. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI'/MOM technique.
Vector meson production in the Golec-Biernat Wuesthoff model
We apply the Golec-Biernat Wuesthoff model in the calculation of vector meson photo- and electroproduction. Starting from very simple non-relativistic wave functions we show that the model provides a good description of J/Ψ cross sections in wide Q2 and W ranges. For the light mesons one obtains the approximately correct W-dependence and ratio of longitudinal to transverse cross sections, although in this case the normalization, affected mainly by the wave function employed, is not in good agreement with data
Electroweak meson production reaction in the nucleon resonance region
We report on our recent study of the the neutrino-nucleon reaction in the nucleon resonance region. The dynamical reaction model of meson production reaction on the nucleon for the pion and photon induced reaction has been developed in order to investigate the spectrum of nucleon excited state. We have extended this model in order to describe the weak meson production reactions with the πN, ηN, KΛ, KΣ and ππN final states. We also studied the role of the final state interaction in the photon and the neutrino induced pion production reaction on the deuteron around the Δ(1232) resonance region
A mathematical model of heavy-Quarkonia mesonic decays
A simple solvable mathematical model is proposed for the mesonic decays of heavy quarkonia. It consists in coupling the bound quark channel and the free decaying meson channel through a contact interaction. The full Hamiltonian is obtained as a self-adjoint extension of the free Hamiltonian, specified by suitable boundary conditions. One obtains a Weisskopf-Van Royen-type formula for the decay width at the lowest order in the interaction strength. Finally the model is shown to remain solvable if a Coulomb interaction is added in the quark channel. 53 refs
A mathematical model of heavy-Quarkonia mesonic decays
Antoine, J.P. (Universite Catholique de Louvain, Louvain-la-Neuve (Belgium)); Exner, P.; Seba, P. (Nuclear Physics Institute, Prague (Czechoslovakia)); Shabani, J. (Unveriste du Burundi, Bujumbura (Burundi))
1994-07-01
A simple solvable mathematical model is proposed for the mesonic decays of heavy quarkonia. It consists in coupling the bound quark channel and the free decaying meson channel through a contact interaction. The full Hamiltonian is obtained as a self-adjoint extension of the free Hamiltonian, specified by suitable boundary conditions. One obtains a Weisskopf-Van Royen-type formula for the decay width at the lowest order in the interaction strength. Finally the model is shown to remain solvable if a Coulomb interaction is added in the quark channel. 53 refs.
Nuclear matter equation of state and -meson parameters
A B Santra; U Lambardo
2005-01-01
We try to determine phenomenologically the extent of in-medium modification of -meson parameters so that the saturation observables of the nuclear matter equation of state (EOS) are reproduced. To calculate the EOS we have used Brueckner–Bethe–Goldstone formalism with Bonn potential as two-body interaction. We find that it is possible to understand all the saturation observables, namely, saturation density, energy per nucleon and incompressibility, by incorporating in-medium modification of -meson–nucleon coupling constant and -meson mass by a few per cent.
Prospects of Bc Mesons at the Compact Muon Solenoid
ZHANG Shao-He; A. A. Belkov; S. Shulga; CHEN Guo-Ming
2004-01-01
@@ The results of two Monte Carlo generators for production of Bc mesons in pp collisions are compared at the large hadron collider energy √s = 14 TeV. In the study, the produced Bc mesons were forced to decay into the final states Bslv, Bsπ, J/ψlv, and J/ψπ. We have estimated that about 104 decays of Bc are expected to be recorded during the first year of the CMS running with a lepton trigger. Many Bc studies can be carried out by using these events with a statistical error at the level of 10-2.
Meson Structure in a Relativistic Many-Body Approach
Llanes-Estrada, F J; Llanes-Estrada, Felipe J.; Cotanch, Stephen R.
2000-01-01
Results from an extensive relativistic many-body analysis utilizing a realistic effective QCD Hamiltonian are presented for the meson spectrum. A comparative numerical study of the BCS, TDA and RPA treatments provides new, significant insight into the condensate structure of the vacuum, the chiral symmetry governance of the pion and the meson spin, orbital and flavor mass splitting contributions. In contrast to a previous glueball application, substantial quantitative differences are computed between TDA and RPA for the light quark sector with the pion emerging as a Goldstone boson only in the RPA.
Meson Structure in a Relativistic Many-Body Approach
Results from an extensive relativistic many-body analysis utilizing a realistic effective QCD Hamiltonian are presented for the meson spectrum. A comparative numerical study of the BCS, Tamm-Dancoff (TDA), and RPA treatments provides new, significant insight into the condensate structure of the vacuum, the chiral symmetry governance of the pion, and the meson spin, orbital, and flavor mass splitting contributions. In contrast to a previous glueball application, substantial quantitative differences are computed between TDA and RPA for the light quark sector with the pion emerging as a Goldstone boson only in the RPA. (c) 2000 The American Physical Society
Mass shift of σ-meson in nuclear matter
The propagation of σ-meson in nuclear matter is studied in the Walecka model, by assuming that sigma couples to a pair of nucleon-antinucleon states to particle-hole states. The in-medium effect of σ-ω mixing is also studied. For completeness, the coupling of sigma to two virtual pions was also considered. It is found that the σ-meson mass decreases with respect to its value in vacuum and that the contribution of the σ-ω mixing effect on the mass shift is relatively small. (author)
The role of meson dynamics in nuclear matter saturation
The problem of the saturation of nuclea matter in the non-relativistic limit of the model proposed by J.D. Walecka is studied. In the original context nuclear matter saturation is obtained as a direct consequence of relativistic effects and both scalar and vector mesons are treated statically. In the present work we investigate the effect of the meson dynamics for the saturation using a Born-Oppenheimer approximation for the ground state. An upper limit for the saturation curve of nuclear matter and are able to decide now essential is the relativistic treatment of the nucleons for this problem, is obtained. (author)
Charmed meson production and decay properties at the psi(3770)
1979-05-01
A remeasurement of the resonance near E/sub cm/ = 3.77 GeV in the e/sup +/e/sup -/ annihilation is presented. The properties of the resonance are used to deduce branching fractions of charmed mesons into hadronic final states. Several previously unseen decay modes are reported. Decays into Cabibbo suppressed final states are observed. The inclusive properties of D meson decays are studied, including strangeness and charged particle multiplicity. The semileptonic branching fractions for D/sup 0/ and D/sup -+/ are measured, providing a determination of the relative lifetimes of these particles.
A precise measurement of the $B^0$ meson oscillation frequency
AUTHOR|(CDS)2075808; Adeva, Bernardo; Adinolfi, Marco; Affolder, Anthony; Ajaltouni, Ziad; Akar, Simon; Albrecht, Johannes; Alessio, Federico; Alexander, Michael; Ali, Suvayu; Alkhazov, Georgy; Alvarez Cartelle, Paula; Alves Jr, Antonio Augusto; Amato, Sandra; Amerio, Silvia; Amhis, Yasmine; An, Liupan; Anderlini, Lucio; Anderson, Jonathan; Andreassi, Guido; Andreotti, Mirco; Andrews, Jason; Appleby, Robert; Aquines Gutierrez, Osvaldo; Archilli, Flavio; d'Argent, Philippe; Artamonov, Alexander; Artuso, Marina; Aslanides, Elie; Auriemma, Giulio; Baalouch, Marouen; Bachmann, Sebastian; Back, John; Badalov, Alexey; Baesso, Clarissa; Baldini, Wander; Barlow, Roger; Barschel, Colin; Barsuk, Sergey; Barter, William; Batozskaya, Varvara; Battista, Vincenzo; Bay, Aurelio; Beaucourt, Leo; Beddow, John; Bedeschi, Franco; Bediaga, Ignacio; Bel, Lennaert; Bellee, Violaine; Belloli, Nicoletta; Belyaev, Ivan; Ben-Haim, Eli; Bencivenni, Giovanni; Benson, Sean; Benton, Jack; Berezhnoy, Alexander; Bernet, Roland; Bertolin, Alessandro; Bettler, Marc-Olivier; van Beuzekom, Martinus; Bien, Alexander; Bifani, Simone; Billoir, Pierre; Bird, Thomas; Birnkraut, Alex; Bizzeti, Andrea; Blake, Thomas; Blanc, Frédéric; Blouw, Johan; Blusk, Steven; Bocci, Valerio; Bondar, Alexander; Bondar, Nikolay; Bonivento, Walter; Borghi, Silvia; Borsato, Martino; Bowcock, Themistocles; Bowen, Espen Eie; Bozzi, Concezio; Braun, Svende; Britsch, Markward; Britton, Thomas; Brodzicka, Jolanta; Brook, Nicholas; Buchanan, Emma; Bursche, Albert; Buytaert, Jan; Cadeddu, Sandro; Calabrese, Roberto; Calvi, Marta; Calvo Gomez, Miriam; Campana, Pierluigi; Campora Perez, Daniel; Capriotti, Lorenzo; Carbone, Angelo; Carboni, Giovanni; Cardinale, Roberta; Cardini, Alessandro; Carniti, Paolo; Carson, Laurence; Carvalho Akiba, Kazuyoshi; Casse, Gianluigi; Cassina, Lorenzo; Castillo Garcia, Lucia; Cattaneo, Marco; Cauet, Christophe; Cavallero, Giovanni; Cenci, Riccardo; Charles, Matthew; Charpentier, Philippe; Chefdeville, Maximilien; Chen, Shanzhen; Cheung, Shu-Faye; Chiapolini, Nicola; Chrzaszcz, Marcin; Cid Vidal, Xabier; Ciezarek, Gregory; Clarke, Peter; Clemencic, Marco; Cliff, Harry; Closier, Joel; Coco, Victor; Cogan, Julien; Cogneras, Eric; Cogoni, Violetta; Cojocariu, Lucian; Collazuol, Gianmaria; Collins, Paula; Comerma-Montells, Albert; Contu, Andrea; Cook, Andrew; Coombes, Matthew; Coquereau, Samuel; Corti, Gloria; Corvo, Marco; Couturier, Benjamin; Cowan, Greig; Craik, Daniel Charles; Crocombe, Andrew; Cruz Torres, Melissa Maria; Cunliffe, Samuel; Currie, Robert; D'Ambrosio, Carmelo; Dall'Occo, Elena; Dalseno, Jeremy; David, Pieter; Davis, Adam; De Aguiar Francisco, Oscar; De Bruyn, Kristof; De Capua, Stefano; De Cian, Michel; De Miranda, Jussara; De Paula, Leandro; De Simone, Patrizia; Dean, Cameron Thomas; Decamp, Daniel; Deckenhoff, Mirko; Del Buono, Luigi; Déléage, Nicolas; Demmer, Moritz; Derkach, Denis; Deschamps, Olivier; Dettori, Francesco; Dey, Biplab; Di Canto, Angelo; Di Ruscio, Francesco; Dijkstra, Hans; Donleavy, Stephanie; Dordei, Francesca; Dorigo, Mirco; Dosil Suárez, Alvaro; Dossett, David; Dovbnya, Anatoliy; Dreimanis, Karlis; Dufour, Laurent; Dujany, Giulio; Dupertuis, Frederic; Durante, Paolo; Dzhelyadin, Rustem; Dziurda, Agnieszka; Dzyuba, Alexey; Easo, Sajan; Egede, Ulrik; Egorychev, Victor; Eidelman, Semen; Eisenhardt, Stephan; Eitschberger, Ulrich; Ekelhof, Robert; Eklund, Lars; El Rifai, Ibrahim; Elsasser, Christian; Ely, Scott; Esen, Sevda; Evans, Hannah Mary; Evans, Timothy; Falabella, Antonio; Färber, Christian; Farley, Nathanael; Farry, Stephen; Fay, Robert; Ferguson, Dianne; Fernandez Albor, Victor; Ferrari, Fabio; Ferreira Rodrigues, Fernando; Ferro-Luzzi, Massimiliano; Filippov, Sergey; Fiore, Marco; Fiorini, Massimiliano; Firlej, Miroslaw; Fitzpatrick, Conor; Fiutowski, Tomasz; Fohl, Klaus; Fol, Philip; Fontana, Marianna; Fontanelli, Flavio; Forshaw, Dean Charles; Forty, Roger; Frank, Markus; Frei, Christoph; Frosini, Maddalena; Fu, Jinlin; Furfaro, Emiliano; Gallas Torreira, Abraham; Galli, Domenico; Gallorini, Stefano; Gambetta, Silvia; Gandelman, Miriam; Gandini, Paolo; Gao, Yuanning; García Pardiñas, Julián; Garra Tico, Jordi; Garrido, Lluis; Gascon, David; Gaspar, Clara; Gauld, Rhorry; Gavardi, Laura; Gazzoni, Giulio; Gerick, David; Gersabeck, Evelina; Gersabeck, Marco; Gershon, Timothy; Ghez, Philippe; Gianì, Sebastiana; Gibson, Valerie; Girard, Olivier Göran; Giubega, Lavinia-Helena; Gligorov, Vladimir; Göbel, Carla; Golubkov, Dmitry; Golutvin, Andrey; Gomes, Alvaro; Gotti, Claudio; Grabalosa Gándara, Marc
2016-01-01
The oscillation frequency, $\\Delta m_d$, of $B^0$ mesons is measured using semileptonic decays with a $D^-$ or $D^{*-}$ meson in the final state, in a data sample of $pp$ collisions collected by the LHCb detector corresponding to an integrated luminosity of 3.0$\\mbox{fb}^{-1}$. A combination of the two decay modes gives $\\Delta m_d = (505.0 \\pm 2.1 \\pm 1.0) \\rm \\,ns^{-1}$, where the first uncertainty is statistical and the second is systematic. This is the most precise single measurement of this parameter. It is compatible with the current world average and has similar precision.
Meson Photoproduction off the Deuteron and off 3He
Photoproduction of mesons off the deuteron and He nuclei has been studied at the tagged photon facilities of the Bonn ELSA accelerator and the Mainz MAMI accelerator with the Crystal/ setup (Mainz). Meson photoproduction off the neutron has been investigated for different final states (πo, πo πo, πo π-, η, η', ηπo). A surprising finding was a narrow structure in the γn→nη excitation function, which is not seen in the proton case. Photoproduction off 3He has provided further evidence for the formation of an h-mesic state.
Electromagnetic production of vector mesons at low energies
The authors have investigated exclusive photoproduction of light vector mesons (ω, ρ and φ) on the nucleon at low energies. In order to explore the questions concerning the so-called missing nucleon resonances, they first establish the predictions from a model based on the Pomeron and meson exchange mechanisms. They have also explored the contributions due to the mechanisms involving s- and u-channel intermediate nucleon state. Some discrepancies found at the energies near threshold and large scattering angles suggest a possibility of using this reaction to identify the nucleon resonances
Modification of meson properties in the vicinty of nuclei
Filip Peter
2014-01-01
Full Text Available We suggest that modification of meson properties (lifetimes and branching ratios can occur due to the interaction of constituent quark magnetic moments with strong magnetic fields present in the close vicinity of nuclei. A superposition of (J =0 and (J =1, mz =0 particle-antiparticle quantum states (as observed for ortho-Positronium may occur also in the case of quarkonium states J/Ψ, ηc ϒ, ηb in heavy ion collisions. We speculate on possible modification of η(548 meson properties (related to C parity and CP violation in strong magnetic fields which are present in the vicinity of nuclei.
The meson spectroscopy program with CLAS12 at Jefferson Laboratory
Rizzo, Alessandro [Univ. of Rome Tor Vergata (Italy)
2016-06-01
The study of the hadronic spectrum is one of the most powerful tools to investigate the mechanism at the basis of quark confinement within hadrons. A precise determination of the spectrum allows not only to assess the properties of the hadrons in their fundamental and excited states, but also to investigate the existence of states resulting from alternative configurations of quarks and gluons, such as the glue-balls, hybrid hadrons and many-quarks configurations. The study of the mesonic part of the spectrum can play a central role in this investigation thanks to the strong signature that the hybrid mesons are expected to have: the presence of explicit gluonic degrees of freedom in such states may result in JPC configurations not allowed for the standard q ¯ q states. From the experimental side the expected high-multiplicity decays of the hybrid mesons require an apparatus with high performances in terms of rate-capability, resolution and acceptance. The CLAS12 experiment (formally MesonEx) is one of new-generation experiments at Thomas Jefferson National Laboratory (JLAB) for which an unprecedented statistics of events, with fully reconstructed kinematics for large particle multiplicity decays, will be available. A wide scientific program that will start in 2016 has been deployed for meson spectrum investigation with the CLAS12 apparatus in Hall B at energies up to 11 GeV. One of the main parts of the program is based on the use of the Forward Tagger apparatus, which will allow CLAS12 experiment to extend the study of meson electro-production to the quasi-real photo-production kinematical region (very low Q2), where the production of hybrid mesons is expected to be favoured. The data analysis which is required to extract the signal from hybrid states should go beyond the standard partial wave analysis techniques and a new analysis framework is being set up through the international network Haspect. The Haspect Network gathers people involved into theoretical and
`Internal` B-meson decays. DIS and HQET approach
Ter-Martirosyan, K.A. [Gosudarstvennyj Komitet po Ispol`zovaniyu Atomnoj Ehnergii SSSR, Moscow (Russian Federation). Inst. Teoreticheskoj i Ehksperimental`noj Fiziki
1994-12-31
Inclusive B-meson decays, in particular of `internal` types (into heavy mesons and baryon pairs),are considered using Deep Inelastic Scattering (DIS) and Heavy Quark Effective Theory (HQET) type approaches. Quite large 12% contribution of these nonleptonic decays (7% only of baryon pairs resulting from diquark production) has been found. This leads to a considerable reduction of the semileptonic decay ratio down to its experimental value, 9%. It explains simultaneously experimental data on the large fraction 7% of B-decays into baryon-antibaryon pairs. The general picture of distributions of b decays branchings of all main types types is presented. (author). 16 refs., 11 figs.
Vector meson inclusive spectra in dual parton model
The inclusive spectra of vector mesons are calculated in the framework of the dual parton model, and their comparison with the experimental data on Kp interaction is carried out. An expression is given to describe hadron distributions in a string, which takes into account the valence nature of quarks, forming the string. This allowance for valence quarks in the string is important up to the ISR energies. It turned out that the regard for the topology of the processes allows one to eliminate the contradiction in model description of K*-meson production in Kp interactions
Testing fundamental physical principles with entangled neutral K mesons
Di Domenico Antonio
2014-01-01
The neutral kaon doublet is one of the most intriguing systems in nature. En- tangled pairs of neutral K mesons produced in ϕ-meson decays offer a unique possibility to perform important tests of fundamental discrete symmetries as well as of basic principles of quantum mechanics. This paper will focus on a novel method to perform direct T and CPT symmetry tests exploiting the Einstein-Podolsky-Rosen correlations of neutral kaon pairs produced at a ϕ-factory. The statistical significance of...
Lattice results for low moments of light meson distribution amplitudes
Arthur, R.; Boyle, P.A. [Edinburgh Univ. (United Kingdom). SUPA, School of Physics; Broemmel, D.; Flynn, J.M.; Rae, T.D.; Sachrajda, C.T.C. [Southampton Univ. (United Kingdom). School of Physics and Astronomy; Donnellan, M.A. [NIC/DESY Zeuthen (Germany); Juettner, A. [CERN, Geneva (Switzerland). Physics Dept.
2010-12-15
As part of the UKQCD and RBC collaborations' N{sub f} = 2+1 domain-wall fermion phenomenology programme, we calculate the first two moments of the light-cone distribution amplitudes of the pseudoscalar mesons {pi} and K and the (longitudinally-polarised) vector mesons {rho}, K{sup *} and {phi}. We obtain the desired quantities with good precision and are able to discern the expected quark-mass dependence of SU(3)-flavour breaking effects. An important ingredient of the calculation is the nonperturbative renormalisation of lattice operators using the RI{sup '}/MOM technique. (orig.)
Charm Fragmentation and Excited Charm Meson Production at HERA
Study of Charm Fragmentation into D*± Mesons in Deep-Inelastic Scattering at HERA The process of charm quark fragmentation is studied using D*± meson production in deep-inelastic scattering as measured by the H1 detector at HERA. Two different regions of phase space are investigated defined by the presence or absence of a jet containing the D*± meson in the event. The parameters of fragmentation functions are extracted for QCD models based on leading order matrix elements and DGLAP or CCFM evolution of partons together with string fragmentation and particle decays. Additionally, they are determined for a next-to-leading order QCD calculation in the fixed flavour number scheme using the independent fragmentation of charm quarks to D*± mesons. Measurement of the charm fragmentation function in D* photoproduction at HERA The charm fragmentation function has been measured in D* photoproduction with the ZEUS detector at HERA using an integrated luminosity of 120 pb-1. The fragmentation function is measured versus z, the ratio of E+pparallel for the D* meson and that for the associated jet, where E is the energy and pparallel the longitudinal momentum relative to the jet axis. Jets were reconstructed using the kT clustering algorithm and required to have transverse energy greater than 9 GeV. The D* meson associated with the jet was required to have a transverse momentum greater than 2 GeV. The measured function is compared to different fragmentation models incorporated in leading-logarithm Monte Carlo simulations and a next-to-leading-order calculation. The results are similar to those from e+e- experiments. Excited charm meson production at HERA The production of the excited charm mesons D1(2420)0 and D2*(2460)0 in inelastic ep scattering was studied with the ZEUS detector at HERA using an integrated luminosity of 372 pb-1. Masses and widths were determined and and a helicity analysis was performed. The results are compared with previous measurements and with
Magnetic dipole moments of the heavy tensor mesons in QCD
Aliev, T.M. [Middle East Technical University, Physics Department, Ankara (Turkey); Institute of Physics, Baku (Azerbaijan); Barakat, T. [Middle East Technical University, Physics Department, Ankara (Turkey); King Saud University, Physics and Astronomy Department, Riyadh (Saudi Arabia); Savci, M. [Middle East Technical University, Physics Department, Ankara (Turkey)
2015-11-15
The magnetic dipole moments of the D{sub 2}, and D{sub S{sub 2}}, B{sub 2}, and B{sub S{sub 2}} heavy tensor mesons are estimated in framework of the light cone QCD sum rules. It is observed that the magnetic dipole moments for the charged mesons are larger than that of its neutral counterpart. It is found that the SU(3) flavor symmetry violation is about 10 % in both b and c sectors. (orig.)
Total cross sections of beauty and charmed mesons on protons
Using a simple scaling law we predict the values of the total cross sections σ(B±p), σBd,s0, σ(bar Bd,s0P), σ(Dd,s±P), σ(D0p), σ(bar D0p) from known total Kp cross sections. We assume that mesons with the same light valence quark, q, and differing only by their heavy valence quark content, Q, have total cross sections on protons which scale as the inverse of the nth power of the reduced mass of the meson. We predict that σ(Q bar q)p > σ(bar Qq)p
Studies of phi meson radiative decays with KLOE
A sample of 5.3 x 107phi mesons, produced at the Frascati phi-factory DAPHINE, has been used by the KLOE Collaboration to study the phi radiative decays. The decays phi → ηπ0γ and phi → πoπoγ have been exploited to study the scalar mesons ao(980) and fo(980). Furthermore a new determination of the η - η' mixing angle has been obtained from the measurement of the ratio of the decay rates of phi → η'γ to phi → ηγ to phi → ηγ
D meson hadronic decays at CLEO-c
Yang, Fan; /Fermilab
2011-01-01
The recent CLEO-c results on hadronic decays of D and D{sub s} mesons are presented. First the absolute branching fractions for D and D{sub s} mesons using a double tag technique are discussed, then are the Cabibbo suppressed decays and doubly Cabibbo suppressed decays. Finally, I present the inclusive and rare decay modes and other measurements from CLEO-c. These decays illuminate a wide range of physics. A brief theoretical introduction is given before the corresponding discussion on measurement.
Hybrid Meson Potentials and the Gluonic van der Waals Force
Lakhina, O
2004-01-01
The chromoelectric polarizability of mesons governs the strength of the gluonic van der Waals force and therefore of non-quark-exchange processes in hadronic physics. We compute the polarizability of heavy mesons with the aid of lattice gauge theory and the Born--Oppenheimer adiabatic expansion. We find that the operator product expansion breaks down at surprisingly large quarks masses due to nonperturbative gluodynamics and that previous conclusions concerning $J/\\psi$--nuclear matter interactions and $J/\\psi$ dissociation in the quark-gluon plasma must be substantially modified.
Open bottom mesons in hot asymmetric hadronic medium
Pathak, Divakar; Mishra, Amruta
2014-01-01
The in-medium masses and optical potentials of $B$ and ${\\bar B}$ mesons are studied in an isospin asymmetric, strange, hot and dense hadronic environment using a chiral effective model. The chiral $SU(3)$ model originally designed for the light quark sector, is generalized to include the heavy quark sector ($c$ and $b$) to derive the interactions of the $B$ and ${\\bar B}$ mesons with the light hadrons. Due to large mass of bottom quark, we use only the empirical form of these interactions fo...
Charmonium dissociation in collision with phi meson in hadronic matter
Ji, Shi-Tao
2016-01-01
The phi-charmonium dissociation reactions in hadronic matter are studied. Unpolarised cross sections for 12 reactions are calculated in the Born approximation, in the quark-interchange mechanism and with a temperature-dependent quark potential. The potential leads to remarkable temperature dependence of the cross sections. With the cross sections and the phi distribution function we calculate the dissociation rates of the charmonia in the interactions with the phi meson in hadronic matter. The dependence of the rates on temperature and charmonium momentum is meaningful to the influence of phi mesons on charmonium suppression.
Masses of heavy-light mesons in Regge phenomenology
The masses of some orbitally and radially excited heavy-light mesons are calculated in Regge phenomenology. The results are in reasonable agreement with the experimental data and those given in many other theoretical approaches. Based on the calculation, we suggest that the recently observed D(2550), D(2600) and D(2760) can be assigned as the charmed members of the 21S0, 23S1 and 13D1 multiplets, respectively. Ds*1(2700)± may be assigned as the charm-strange member of the 23S1 state. The results may be helpful in understanding the nature of current and future experimentally observed heavy-light mesons. (authors)
D-Meson Production from Recombination in Hadronic Collisions
Rapp, R
2003-01-01
Nonperturbative effects in $D$-meson production in pion-nucleon and proton-nucleon collisions are investigated within the recombination model. The coalescence of perturbatively created charm quarks with sea- and valence-quarks from projectile and target fragments is shown to be competitive in magnitude with standard fragmentation calculations at both central (small $x_F$) and forward rapidities. Corresponding flavor asymmetries for inclusive $D$-meson production are thus mostly generated on the (light-) parton distribution level, and turn out to be in reasonable overall agreement with available fixed-target data. Predictions for upcoming measurements at RHIC are given.
Flavour tagging of $b$ mesons in $pp$ collisions at LHCb
Mueller, Vanessa
2016-01-01
Flavour tagging, i.e. the inference of the production flavour of reconstructed $b$ hadrons, is essential for precision measurements of decay time-dependent $CP$ violation and of mixing parameters in the the neutral $B$ meson systems. LHC's $pp$ collisions with their high track multiplicities constitute a challenging environment for flavour tagging and demand for new and improved strategies. We present recent progress and new developments in flavour tagging at the LHCb experiment, which will allow for a further improvement of $CP$ violation measurements in decays of $B^0$ and $B_s^0$ mesons.
Charmonium dissociation by mesons in heavy-ion collisions
Lykasov, Gennady I.; Cassing, Wolfgang
2006-01-01
The charmonium dissociation by mesons in relativistic heavy-ion reactions is analyzed within the Regge approach. It is shown that the inclusion of the initial and final state interactions in the dissociation of J/Psi to bar{D}* D* close to threshold increases the cross section significantly and can not be neglected in comparison to the total dissociation rate. This is due to resonant bar{D}*-D* interactions in sqrt{s} close to the masses of the Psi(4.04) and Psi(4.16) mesons. We also investig...
Next-to-leading order corrections in exclusive meson production
We analyze in detail the size of next-to-leading order corrections to hard exclusive meson production within the collinear factorization approach. Corrections to the cross section are found to be huge at small xB and substantial in typical fixed-target kinematics. With the models we take for nucleon helicity-flip distributions, the transverse target polarization asymmetry in vector meson production is strongly affected by radiative corrections, except at large xB. Its overall size is very small for ρ production but can be large in the ω channel. (orig.)
Arguments on the Light-mass Scalar Mesons and Concluding Remarks of the Meson Sessions
Tuan, S F
2003-01-01
This report attempts to summarize the most interesting (and hopefully important) results leading up to and including those presented at the recent Symposium sponsored jointly by the Institute of Quantum Science at Nihon University and KEK. My task is to present the arguments on light-mass scalar mesons below 1 GeV from both theory and phenomenological viewpoints, including the new insight gained on $\\pi-\\pi$ production and scattering amplitudes. Specific topics are taken up, particularly on the existence of a $\\sigma$(500-600) as explanation of the twin peak anomaly in $\\Upsilon(3S) \\to \\Upsilon(1S)\\pi\\pi$, the status of $J^{PC}=1^{-+}$ states and a possible crypto-exotic hybrid with $J^{PC}=0^{-+}$ are discussed, as well as the intriguing enhancement in $p\\bar{p}$ radiative decay from $J/\\psi$.
Scalar meson f{sub 0}(980) in heavy-meson decays.
El-Bennich, B.; Leitner, O.; Dedonder, J.-P.; Loiseau, B.; Physics; Lab. de Physique Nucleaire et de Hautes Energies; Lab. Nazionali di Frascati
2009-04-01
A phenomenological analysis of the scalar meson f{sub 0}(980) is performed that relies on the quasi-two-body decays D and D{sub s} {yields} f{sub 0}(980)P, with P = {pi}, K. The two-body branching ratios are deduced from experimental data on D or D{sub s} {yields} {pi}{pi}{pi}, K{sup -} K{pi} and from the f{sub 0}(980) {yields} {pi}{sup +}{pi}{sup -} and f{sub 0}(980) {yields} K{sup +}K{sup -} branching fractions. Within a covariant quark model, the scalar form factors for the transitions D and D{sub s} {yields} f{sub 0}(980) are computed. The weak D decay amplitudes, in which these form factors enter, are obtained in the naive factorization approach assuming a q{bar q} state for the scalar and pseudoscalar mesons. They allow to extract information on the f{sub 0}(980) wave function in terms of u{bar u}, d{bar d}, and s{bar s} pairs as well as on the mixing angle between the strange and nonstrange components. The weak transition form factors are modeled by the one-loop triangular diagram using two different relativistic approaches: covariant light-front dynamics and dispersion relations. We use the information found on the f{sub 0}(980) structure to evaluate the scalar and vector form factors in the transitions D and D{sub s} {yields} f{sub 0}(980), as well as to make predictions for B and B{sub s} {yields} f{sub 0}(980), for the entire kinematically allowed momentum range of q{sup 2}.
Inclusive decays of the B meson and possible life-time difference between Bd0 and B± mesons
We study branching ratios of the inclusive semileptonic decay and the inclusive anti ccanti s decay of the B meson in the spectator model, focusing on the life-time difference between Bd0 and B+ mesons. In the case of τsub(B±)/τsub(Bd0)=1, it is impossible to get the branching ratio below 12% for B→eνX without going over 20% for B→anti ccanti s, which is unfavored by the inclusive K- decay of the B meson. It is found that the sizable life-time difference leads to the reasonable inclusive semileptonic decay rate and the inclusive anti ccanti s decay rate. (orig.)
Observation and study of bottom-meson decays to a charm meson, a proton-antiproton pair, and pions
Hong, Tae Min [Univ. of California, Santa Barbara, CA (United States)
2010-04-27
Bottom-meson decays with baryons show two unusual features—the branching fractions are enhanced for multibody decays and the baryon-antibaryon subsystem recoils against the other decay products—and their reasons are not yet well understood. Moreover, measurements using explicit reconstruction techniques constitute only about 1% out of about 8% of such decays. This Dissertation reports the study of ten bottom-meson decays (labeled 0– 9) to a proton-antiproton pair, a charm meson, and a system of up to two pions, using the BABAR Experiment’s 455×10^{6} BB pairs produced with the PEP-II asymmetric-energy e^{+}e^{- }collider at the Stanford Linear Accelerator Center.
Bottom quark mass from Υ mesons
The bottom quark pole mass Mb is determined using a sum rule which relates the masses and the electronic decay widths of the Υ mesons to large n moments of the vacuum polarization function calculated from nonrelativistic quantum chromodynamics. The complete set of next-to-next-to-leading order [i.e., O(αs2,αsv,v2) where v is the bottom quark c.m. velocity] corrections is calculated and leads to a considerable reduction of theoretical uncertainties compared to a pure next-to-leading order analysis. However, the theoretical uncertainties remain much larger than the experimental ones. For a two parameter fit for Mb, and the strong M bar S coupling αs, and using the scanning method to estimate theoretical uncertainties, the next-to-next-to-leading order analysis yields 4.74 GeV ≤Mb≤4.87 GeV and 0.096≤αs(Mz)≤0.124 if experimental uncertainties are included at the 95% confidence level and if two-loop running for αs is employed. Mb and αs have a sizable positive correlation. For the running M bar S bottom quark mass this leads to 4.09 GeV ≤mb(MΥ(1S)/2)≤4.32 GeV. If αs is taken as an input, the result for the bottom quark pole mass reads 4.78 GeV ≤Mb≤4.98 GeV[4.08 GeV ≤mb(MΥ(1S)/2)≤4.28 GeV] for 0.114≤αs(Mz)≤0.122. The discrepancies between the results of three previous analyses on the same subject by Voloshin, Jamin, and Pich and Kuehn et al. are clarified. A comprehensive review on the calculation of the heavy-quark - antiquark pair production cross section through a vector current at next-to-next-to leading order in the nonrelativistic expansion is presented. copyright 1998 The American Physical Society
Chudakov, Eugene A. [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States); Gevorkyan, Sergey [Joint Inst. for Nuclear Research (JINR), Dubna (Russian Federation); Somov, Alexander [Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
2016-01-01
We consider photoproduction of omega mesons off complex nuclei to study interactions of transversely and longitudinally polarized vector mesons with nucleons. Whereas the total cross section for interactions of the transversely polarized vector mesons with nucleons sigma_T = sigma(V_T N) can be obtained from coherent photoproduction, measurements of vector meson photoproduction in the incoherent region provide a unique opportunity to extract the not-yet-measured total cross section for longitudinally polarized mesons sigma_L = sigma(V_L N). The predictions for the latter strongly depend on the theoretical approaches. This work is stimulated by the construction of the new experiment GlueX at Jefferson Lab, designed to study the photoproduction of mesons in a large beam energy range up to 12 GeV.
Collision times in pi-pi and pi-K scattering and spectroscopy of meson resonances
Kelkar, N G; Khemchandani, K P
2003-01-01
Using the concept of collision time (time delay) introduced by Eisenbud and Wigner and its connection to on-shell intermediate unstable states, we study mesonic resonances in pi-pi and pi-K scattering. The time-delay method proves its usefulness by revealing the spectrum of the well-known rho- and K*-mesons and by supporting some speculations on rho-mesons in the 1200 MeV region. We use this method further to shed some light on more speculative meson resonances, among others the enigmatic scalars. We confirm the existence of chiralons below 1 GeV in the unflavoured and strange meson sector.
Performance and study of B meson spectra in pp and pPb collisions in CMS
Innocenti, Gian Michele
2014-01-01
B meson reconstruction is of great interest in the heavy ion collisions. Measurement of B meson pseudorapidity and transverse momentum spectra can provide useful inputs for the study flavor dependence of jet quenching in PbPb collisions and for the determination of the heavy flavor nuclear parton distribution functions in pPb collisions. The performance of excusive B meson reconstruction with the CMS detector is reported. The B mesons are fully reconstructed with J/$\\psi$ (via di-muon channel) and charged tracks. The background suppression techniques and analysis methods of B meson spectra are discussed in this poster.
Radiative decays of vector mesons in the relativistic harmonic oscillator model
Govorkov, A.B.; Drenska, S.B.
1977-10-01
Radiative M1 transitions both of ordinary vector mesons ..omega.., rho/sup 0/, K/sup 0/*, and also of the new J/psi meson into pseudoscalar mesons ..pi../sup 0/, eta, eta', and K/sup 0/ are discussed in terms of the relativistic model of a four-dimensional harmonic oscillator. The parameters of the oscillator were determined from the experimental data on the decay widths of vector mesons into a lepton pair. For the J/psi meson the relativistic effects lead to an appreciable additional suppression of radiative transitions.
We calculate the branching ratio of a bottom hadron decaying into a charmed hadron and a charged ρ meson within the QCD factorization approach. We consider the effect of the finite width correction of the ρ meson. Our numerical calculation shows an obvious correction because of this effect. We find that the finite width effect of the ρ meson reduces the branching ratios by about 9 % to 11 % for bottom meson decay channels: B+ → D0ρ+, B0 → D-ρ+, and B0s → D-sρ+, and increases the branching ratio by about 10 % for Λb0 → Λc+ρ-. (orig.)
Low-energy photoproduction of omega-mesons
Barth, J; Glander, K H; Hannappel, J; Jöpen, N; Klein, F; Lawall, R; Menze, D; Neuerburg, W; Ostrick, M; Paul, E; Schulday, I; Schwille, W J; Wiegers, B; Ernst, J; Kalinowsky, H; Klempt, E; Link, J; Pee, H V; Klein, F J; Wieland, F W; Wisskirchen, J; Wu, C
2003-01-01
The photoproduction of the vector meson omega has been studied between threshold and W=2.4 GeV with the SAPHIR detector at the Bonn electron stretcher ring ELSA. Besides, the total cross-sections angular distributions in the CMS and decay angular distributions in the helicity and Gottfried-Jackson systems have been measured.
Search for b→s gluon in B meson decays
Using the ARGUS detector at the e+e- storage ring DORIS II at DESY, a search for penguin decays of B mesons involving b → s gluon has been performed. No evidence for the penguin mechanism was found and a number of upper limits are quoted. (orig.)
FERMILAB: operation resumes in meson area; fast neutron therapy
Improvements and modifications in the Meson Area at Fermilab are described. The target train was rebuilt and energy range of some beams raised to 400 GeV with provisions for Tevatron beams of 1000 GeV in the future. The work of the fast neutron therapy facility is summarised. (W.D.L.).
$\\pi$ and $\\pi\\pi$ Decays of Excited D Mesons
Lähde, T A
2002-01-01
The $\\pi$ and $\\pi\\pi$ decay widths of the excited charm mesons are calculated using a Hamiltonian model within the framework of the covariant Blankenbecler-Sugar equation. The pion-light constituent quark coupling is described by the chiral pseudovector Lagrangian.
Relativistic bound states: a mass formula for vector mesons
In the framework of a relativistic description of two particles bound states, a mass formula for vector mesons considered as quark-antiquark systems bound by harmonic oscillator like forces is proposed. Results in good agreement with experimental values are obtained
High-energy exclusive leptoproduction of vector mesons
The physics of diffractive vector meson production in virtual photon nucleon scattering at NMC energies is reviewed. A particular attention is paid to the physical aspects of the reaction and how they influence the observables. The reaction is a good probe to investigate both soft exchange mechanisms and hadronic wave functions. Extension to either HERA or ELFE kinematics is sketched out. (orig.)
Neutron targets of Moscow meson facility status, problems, prospects
The status, problems and possible perspectives of target complexes of the Moscow meson factory is described in the report. The results of test proton beam session to neutron source are analysed. Some technical features of targets and expected modes in the nearest sessions are stated. (author)
An improved model of vector mesons in holographic QCD
Alvares, Raul; Karch, Andreas
2011-01-01
We analyze the sector of dimension-three vector meson operators in the "hard wall" model of holographic QCD, including the vector and axial currents, dual to gauge fields in the bulk, and the tensor operator $\\bar{\\psi}\\sigma^{\\mu\