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Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

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At least 1,063 records · Page 59
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DOE OSTI2011

Chiral extrapolation of elastic meson-meson scattering: phase shifts and resonance poles

We study the dependence of the {pi}{pi} scattering phase shifts on the light quark mass in both standard and unitarized SU(2) Chiral Perturbation Theory (ChPT) to one and two loops. We then use unitarized SU(3) ChPT to study the elastic f{sub 0}(600),{kappa}(800), {rho}(770) and K*(892) resonances. The quark masses are varied up to values of interest for lattice studies. We find a very soft dependence on the light quark mass of the {pi}{pi} phase shifts as a function of the center of mass momentum at one loop and slightly stronger at two loops and a good agreement with lattice results. The SU(3) analysis shows that the properties of the {rho}(770) and K*(892) depend smoothly on the quark mass whereas the scalar resonances present a non-analyticity at high quark masses. We also confirm the lattice assumption of quark mass independence of the vector two-meson coupling that, however, is violated for scalars.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Precision measurements of kaon radiative decays

We report the recent results of the NA48/2 experiment on charged kaon radiative decays. Using data collected during 2003 and 2004, precise measurements of the K{sup {+-}{yields}{pi}{+-}{pi}0{gamma}} and K{sup {+-}{yields}{pi}{+-}{gamma}{gamma}} decays properties have been obtained.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Quark fragmentation to pions and kaons in the NJL-jet model

We describe the quark fragmentation functions to pions and kaons in the NJL-jet model and compare the results with empirical parametrizations. By including cascade-like fragmentation processes, the momentum and isospin sum rules can be satisfied naturally without introducing new parameters into the theory. We associate a low energy scale with the NJL model, and perform the Q{sup 2} evolution in leading order. The results are in reasonable agreement with the empirical fragmentation functions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Recent Results on Light Hadron Spectroscopy at BESIII

Using about 226x10{sup 6} J/{psi} events and 106x10{sup 6} {psi}{sup '} events accumulated with BESIII detector operating at BEPCII e{sup +}e{sup -} collider, the existence of pp-bar mass threshold enhancement and X(1835) is confirmed. Two new resonances, X(2120) and X(2370) are also observed in J/{psi}{yields}{gamma}{eta}{sup '}{pi}{sup +}{pi}{sup -}. In the analysis of J/{psi}{yields}{omega}{eta}{pi}{sup +}{pi}{sup -}, a new process J/{psi}{yields}{omega}X(1870){yields}{omega}a{sub 0}(980){pi} is seen with a significance of 7.7{sigma}. In addition, a direct measurement of f{sub 0}(980){yields}a{sub 0}{sup 0}(980) and a{sub 0}{sup 0}(980){yields}f{sub 0}(980) mixing transitions is presented to probe the properties of these two scalar states.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Scalar-Pseudoscalar scattering and pseudoscalar resonances

The interactions between the f{sub 0}(980) and a{sub 0}(980) scalar resonances and the lightest pseudoscalar mesons are studied. We first obtain the interacting kernels, without including any ad hoc free parameter, because the lightest scalar resonances are dynamically generated. These kernels are unitarized, giving the final amplitudes, which generate pseudoscalar resonances, associated with the K(1460), {pi}(1300), {pi}(1800), {eta}(1475) and X(1835). We also consider the exotic channels with I = 3/2 and I{sup G} = 1{sup +} quantum numbers. The former could be also resonant in agreement with a previous prediction.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

f{sub 0}(600) and f{sub 0}(980) pole positions from a dispersive {pi}{pi} scattering data analysis

We show how the new precise data on kaon decays together with forward dispersion relations, sum rules and once- and twice-subtracted Roy equations allow for a precise analysis of {pi}{pi} scattering. The once subtracted Roy equations provide a more stringent consistency check for the parametrizations of the S0-wave data in the region from 450 to 1100 MeV that allows us to present a preliminary determination of the f{sub 0}(600) and f{sub 0}(980) poles from the constrained dispersive data analysis.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Light meson spectroscopy and Regge trajectories in the relativistic quark model

Masses of light tetraquarks are obtained in the diquark-antidiquark picture. Such exotic states can be identified with the known light scalar mesons forming an SU(3) nonet ({sigma} meson f{sub 0}(600),{kappa} meson K{sub 0}*(800), f{sub 0}(980) and a{sub 0}(980)). Mass spectra of light (u,d,s) quark-antiquark mesons are calculated within the QCD-motivated relativistic quark model. Their Regge trajectories exhibit linearity and equidistance.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Holography and the (g-2){sub {mu}}

I report on an ongoing program to determine the hadronic contributions to the (g-2){sub {mu}} from models of holographic QCD. These models offer a unique framework to provide a complete calculation of all the different contributions involved, both in the vaccum polarization and the light-by-light scattering (HLBL). Here I present results on the {pi}{sup 0{gamma}{gamma}} form factor and the pion exchange contribution to HLBL. The uncertainty induced on (g-2){sub {mu}} by the low energy slope of {pi}{sup 0{gamma}{gamma}} and the parameter {chi}{sub 0} is discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Quark mass dependence of light and heavy systems

The pion mass dependence of the pion vector form factor is investigated using the Omnes representation. Our prediction agrees with later lattice results quite well. The nice agreement of the pion mass dependence of the scattering lengths of the charmed mesons and light pseudoscalar mesons suggests that the D{sub s0}(2317)* be a DK bound state. Furthermore, it is argued that the kaon mass dependence of a kaonic bound state should be linear, and can be used as a criterion in determining the nature of such a bound state on lattice.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Kaon condensation in CFL quark matter, the Goldstone theorem, and the 2PI Hartree approximation

At very high densities, QCD is in the color-flavor-locked phase, which is a color-superconducting phase. The diquark condensates break chiral symmetry in the same way as it is broken in vacuum QCD and gives rise to an octet of pseudo-Goldstone bosons and a superfluid mode. The lightest of these are the charged and neutral kaons. For energies below the superconducting gap, the kaons are described by an O(2)xO(2)-symmetric effective scalar field theory with chemical potentials. We use this effective theory to study Bose-condensation of kaons and their properties as functions of the temperature and the chemical potentials. We use the 2-particle irreducible effective action formalism in the Hartree approximation. The renormalization of the gap equations and the effective potential is studied in detail and we show that the counterterms are independent of temperature and chemical potentials. We determine the phase diagram and the medium-dependent quasiparticle masses. It is shown that the Goldstone theorem is satisfied to a very good approximation.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Analyticity constraints on the in-medium spectrum of mesons

Analyticity constraints in the form of energy weighted sum rules for the spectral function of mesons are derived, both in cold nuclear matter and at finite temperature, by matching the Dyson propagator with its spectral Lehmann representation at low and high energies. We illustrate our results by calculating the sum rules for specific models of the kaon and pion self-energy in a nuclear medium. We find satisfactory results from the lower energy weight sum rules, which reflect the contributions from the different quasi-particle and collective modes of the meson spectral function, and show examples of the sensitivity of the sum rules to model approximations. Finally, we discuss applications in asymmetric nuclear matter and in the study of the spectral properties of vector mesons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The Dynamical Nonlocality of Neutral Kaons and the Kaonic Quantum Eraser

Testing quantum foundations for systems in high energy physics gets currently more and more attention e.g. witnessed for entangled neutral K-mesons by the approved programme of the KLOE collaboration at the accelerator facility DAPHNE (Frascati, Italy). We focus on this quantum system in high energy physics and discuss two topics, Bell inequalities and the kaonic quantum eraser, and show how the neutral kaon system differs from systems of ordinary matter and light. In detail, we show a relation of the imbalance of matter and antimatter to the violation of a Bell inequality and discuss another Bell inequality which is maximally violated for a non-maximally entangled state though neutral kaons can be considered as two state systems. We compare in general this system in high energy physics with bipartite qudits. Last but not least we review the quantum marking and eraser procedure and explain why neutral kaons offer more eraser possibilities than usual quantum systems.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2011

A Very High Momentum Particle Identification Detector for the ALICE experiment

The main purpose of the ALICE experiment at CERN is to identify and study the quark-gluon plasma (QGP) in heavy ion collisions at the LHC. Among others, hadrochemistry allows for a detailed insight into the characteristics of the high temperature and density system created in these events. It is therefore important to be able to identify charged particles on a track by track basis. Moreover, results from high energy nucleus-nucleus collisions obtained by other experiments (e.g. at RHIC) indicate that it is imperative to extend the detection capability of ALICE to higher momenta. To meet these challenges, we propose the construction of the Very High Momentum Particle Identification Detector (VHMPID), which aims to identify charged pions, kaons, protons and antiprotons in the momentum range of 10 GeV/c<p{sub T}<30 GeV/c. In this contribution we will review the relevant physics arguments in proton-proton and heavy ion collisions as well as the detector proposal based on a RICH (Ring Imaging Cherenkov) detector with a C{sub 4}F{sub 10} radiator and a MWPC based CsI photon counter. In addition, we will present the advances in the development of an alternative multi-THGEM based CsI photon detector.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Charged particles produced in quark and gluon jets in proton-proton collisions

We investigate whether and how different fragmentation properties of quarks and gluons affect identified particle spectra. We present a systematic study of {pi}, K and p production in minimum bias (inelastic, non-diffractive), two- and three-jet events at RHIC, Tevatron and LHC energies. Through the study of two- and three-jet events and various jet-production channels we can directly access the fragmentation properties of quark and gluon jets. We present MC estimate for the contribution of quark and gluon jets to individual particle species spectra, that can be compared to experimental results and test our current knowledge of the physics behind particle production inside jets.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

J-PARC Status, Nuclear and Particle Physics

J-PARC accelerator research complex, consisting of LINAC, RCS and MR synchrotron, has successfully produced neutron, muons, kaons, and neutrinos by steady commissioning since November 2006. There are three experimental facilities, and for nuclear and particle physics, nine experiments are approved in a hadron physics facility, and one experiment is approved in a neutrino physics facility. Those experiments and status of J-PARC are described in this paper.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Monte-Carlo Approach to Calculating the Fragmentation Functions in NJL-Jet Model

Recent studies of the fragmentation functions using the Nambu-Jona-Lasinio (NJL)-Jet model have been successful in describing the quark fragmentation functions to pions and kaons. The NJL-Jet model employs the integral equation approach to solve for the fragmentation functions in quark-cascade description of the hadron emission process, where one assumes that the initial quark has infinite momentum and emits an infinite number of hadrons. Here we introduce a Monte Carlo (MC) simulation method to solve for the fragmentation functions, that allows us to relax the above mentioned approximations. We demonstrate that the results of MC simulations closely reproduce the solutions of the integral equations in the limit where a large number of hadrons are emitted in the quark cascade. The MC approach provides a strong foundation for the further development of the NJL-Jet model that might include many more hadronic emission channels with decays of the possible produced resonances, as well as inclusion of the transverse momentum dependence (TMD), all of which are of considerable importance to the experimental studies of the transverse structure of hadrons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Hadron spectroscopy in diffractive and central production processes at COMPASS

COMPASS is a fixed-target experiment using secondary high-energetic hadron beams provided by the CERN SPS. In 2008 and 2009, a large amount of data has been collected with a 190 GeV/c pion beam for the investigation of the hadron spectrum in diffractive and central production processes. A big variety of observed final states, including {pi}{sup -}{pi}{sup +}{pi}{sup -}, {pi}{sup -}{pi}{sup 0}{pi}{sup 0}, {pi}{sup -}{eta}{eta}, {pi}{sup -}K{sub s}K{sub s}, {pi}{sup -}K{sup +}K{sup -}, K{sup -}{pi}{sup +}{pi}{sup -}, and centrally produced 4{pi}, is being analysed. The potential for systematic spectroscopic studies especially concerning the existence and nature of spin-exotic, hybrid and glueball states is discussed. In addition, we show the first results from the data set collected with a proton beam in 2008. These data indicate the chance of COMPASS to contribute to the field of baryon spectroscopy.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The Structure of Excited 0{sup +} States in Nuclei and the Effect of the {gamma} Degree of Freedom

The physics of intrinsic states, within the pairing gap of deformed nuclei with N{approx}90 neutrons, is discussed in the light of the recent realization that the first excited 0{sub 2}{sup +} states in these nuclei are not {beta}-vibrations but four quasi-neutron states. The properties of {gamma}-vibration K{sup {pi}} = 2{sup +} bands is discussed. A method of measuring two proton transfer in high resolution using the ({sup 3}He,n) reaction is proposed.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗