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Results for “MESON-MESON INTERACTIONS”

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 37 records · Page 2
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DOE OSTI2010

Multi-Antikaonic Nuclei and Kaon Condensation in Dense Matter

The structure of multi-antikaonic nuclei (MKN) is investigated in a relativistic mean-field theory coupled with the nonlinear K{sup -} field by the use of effective chiral Lagrangian. The effects of the {Lambda}(1405) range terms on the structure of the MKN are taken into account. It is shown that baryon number density exceeds three times the normal saturation density in the central region of the MKN that a neutron skin structure becomes remarkable as the number of the embedded K{sup -} mesons increases. The similarity difference between the MKN kaon condensation in neutron stars are discussed.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

NA48/2 Results and NA62 Perspectives

Recent results on rare and radiative {Kappa}{sup {+-}} decays from the NA48/2 experiment are reported. Among many rare decay modes, the analysis of {Kappa}{sup {+-}}{yields}{pi}{sup +}{pi}{sup -}e{sup {+-}}{nu} ({Kappa}{sub e4}) decays allows a quasi model-independent approach to the study of low energy {pi}{pi} scattering. With more than 1 million {Kappa}{sub e4} decays the form factors and their energy dependence are measured with an improved precision. In the channel {Kappa}{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup 0}{gamma} more than 1 million decays were reconstructed, leading to the first measurement of the interference between direct photon emission and inner bremsstrahlung contributions as well as new limits on CP violation. For {Kappa}{sup {+-}}{yields}{pi}{sup {+-}}{gamma}{gamma}, a precise measurement of the branching fraction was performed, based on more than 1000 events. In addition the perspectives of NA62 to measure the branching ratio of the very rare kaon decay {Kappa}{sup +}{yields}{pi}{sup +}{nu}{nu} at the CERN SPS are described.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

The f{sub 0}(1370), f{sub 0}(1710), f{sub 2}(1270), f{sub 2}{sup '}(1525), and K{sub 2}{sup *}(1430) as dynamically generated states from vector meson-vector meson interaction

We report on some recent developments in understanding the nature of the low-lying mesonic resonances f{sub 0}(1370), f{sub 0}(1710), f{sub 2}(1270), f{sub 2}{sup '}(1525), and K{sub 2}*(1430). In particular we show that these five resonances can be dynamically generated from vector meson-vector meson interaction in a coupled-channel unitary approach, which utilizes the phenomenologically very successful hidden-gauge Lagrangians to produce the interaction kernel between two vector mesons, which is then unitarized by the Bethe-Salpeter-equation method. The data on the strong decay branching ratios, total decay widths, and radiative decay widths of these five states, and on related J/{psi} decay processes can all be well described by such an approach. We also make predictions, compare them with the results of earlier studies, and highlight observables that if measured can be used to distinguish different pictures of these resonances.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Hidden and open charm meson spectrum

We present a systematic and self-consistent analysis of four-quark charmonium states and applied it to study compact four-quark systems and meson-meson molecules. Our results are robust and should serve to clarify the situation of charmonium spectroscopy above the threshold production of charmed mesons.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Nucleon resonances from three-hadron interactions

Our study of meson-meson-baryon systems with total strangeness zero revealed that many nucleon resonances can be understood as dynamically generated states of three-hadrons. We considered {pi}{pi}N,{pi}{eta}N,{pi}K{Lambda}, and {pi}K{Sigma} as coupled channels and solved the Fadeev equations. To be precise, the study lead to dynamical generation of N*(1710), N*(2100), {Delta}(1910) along with a new isospin 1/2 resonance around 1920 MeV. In this manuscript I briefly review the formalism we use for three-body calculations and the results obtained for the nucleon resonances.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Quark mass dependence of light resonances and phase shifts in elastic {pi}{pi} and {pi}K scattering

We study the light quark mass dependence of the {pi}{pi} scattering phase shifts in standard one and two-loop SU(2) Chiral Perturbation Theory (ChPT). We then repeat the study with unitarized ChPT and, furthermore, we extend the analysis to SU(3) and generate the elastic f{sub 0}(600),{kappa}(800), {rho}(770) and K*(892) resonances from unitarization. The quark masses are varied up to values of interest for lattice studies. We find that the SU(2){pi}{pi} phase shifts both in standard and unitarized ChPT depend very softly on the pion mass and that our results are in fair agreement with lattice results in the I = 2, J = 0 channel. In the SU(3) amplitudes, the mass and width of the {rho}(770) and K*(892) present an analogous and smooth quark mass dependence. In contrast, both scalars present a similar non-analyticity at high quark masses. We also confirm the lattice assumption of independence of the vector two-meson coupling on the quark mass, that is, nevertheless, violated for scalars.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Studying the decay mode of the J/{psi} into a vector meson and a tensor resonance

The decay mode of the J/{psi} into a vector meson and a tensor resonance is presented. The tensor resonances are considered as dynamically generated states from the vector meson-vector meson interaction provided by the hidden gauge formalism upon unitarization in coupled channels. The couplings of the resonances to the pairs of vector-vector building blocks were evaluated in a previous work. Four ratios of partial decay widths are evaluated using one parameter and compared with experimental data including BES collaboration. The theoretical results are compatible with present experimental data.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

S-wave pion exchange and its implications for quarkonium spectroscopy

Pion exchange in S-wave between hadrons that are themselves in S-wave may result in strong physical effects. Previously it was conjectured that this dynamics could lead to deeply bound quasi-molecular states. More recent studies suggest that the dynamics will result in a large non-resonant background rather than in bound states.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

A molecular interpretation for the D{sub s2}*(2573) and the prediction of novel exotic charmed mesons

In this talk we review the vector-vector interaction within the hidden gauge formalism in a coupled channel unitary approach. We study the vector-vector interaction for all the sectors not studied before: C = 0; S 1(hidden-charm), C = 1, S = 1, and the flavor exotic sectors C = 1; S = -1,2 and C = 2; S = 0,1,2. By looking for poles in the complex plane, we find nine states, four of them in the C = 1; S = 1 sector, where one can be identified with the D{sub s2}{sup *}(2573) and it is interpreted as a D*K* molecular state. The other five resonances are found in the flavor exotic sectors C = 1; S = -1, C = 2; S = 0,1 and can be considered as D*K-bar*, D*D* and D{sub s}{sup *}D* molecular states. Nevertheless, there is not experimental evidence of such states yet.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Precision measurements of kaon radiative decays at NA48/2

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

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2010

Precision measurement of {pi}{pi} scattering lengths at the NA48/2 experiment

The NA48/2 experiment at CERN [1] collected {approx}18{center_dot}10{sup 9} charged kaon decays during the years 2003/4. Along with the primary goals of the collaboration, i.e. the measurement of the CP-violating asymmetry in the K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup +}{pi}{sup -} and K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup 0}{pi}{sup 0} decays thanks to the simultaneous collection of K{sup +} and K{sup -} events, the collected data allowed to perform many other interesting analyses. In this paper two independent measurements of {pi}{pi} scattering lengths will be reviewed, using NA48/2 data from the K{sup {+-}}{yields}e{sup {+-}}{nu}{pi}{sup +}{pi}{sup -} decay and from the cusp effect in K{sup {+-}}{yields}{pi}{sup {+-}}{pi}{sup +}{pi}{sup -} respectively.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

SU(6) superset of SU(3) x SU(2) and SU(8) superset of SU(4) x SU(2) Clebsch-Gordan coefficients

Tables of scalar factors are presented for 63 x 63 and 120 x 63 in SU(8) superset of SU(4) x SU(2), and for 35 x 35 and 56 x 35 in SU(6) superset of SU(3) x SU(2). Related tables for SU(4) superset of SU(3) x U(1) and SU(3) superset of SU(2) x U(1) are also provided so that the Clebsch-Gordan coefficients can be completely reconstructed. These are suitable to study meson-meson and baryon-meson interactions within a spin-flavor symmetric scheme.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Dispersive analysis of the new Belle {gamma}{gamma}{yields}{pi}{pi} results with chiral constraints

We present an analysis of the recent high-statistics {gamma}{gamma}{yields}{pi}{pi} data from the Belle collaboration, based on the method of matching dispersive Muskhelishvili-Omnes type equations and chiral expansion formulas, extended beyond the region of {pi}{pi} elastic scattering. Chiral constraints which derive from the knowledge of all of the p{sup 4} and one of the relevant p{sup 6} coupling constants are implemented. Values of the pion dipole as well as quadrupole polarizabilities are deduced.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

Positivity constraints on LECs of {chi}PT lagrangian at O(p{sup 6}) level

Positivity constraints on the LECs of O(p{sup 6}){chi}PT lagrangian are discussed. We demonstrate that the constraints are automatically satisfied inside the Mandelstam triangle for {pi}{pi} scatterings, when N{sub C} is large. Numerical tests are made in the N{sub C} = 3 case, and it is found that these constraints are also well respected.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
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

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

The Y(3940), Z(3930) and the X(4160) as dynamically generated resonances from the vector-vector interaction

We apply a unitary approach together with a set of hidden-gauge Lagrangians to study the vector-vector interaction. Concretely, we focus on the sector with quantum numbers charm C = 0 and strangeness S = 0 in the region around 4000 MeV. We get five poles, three of which could be identified with the Y(3940), Z(3930) and X(4160). These poles appear with quantum numbers I = 0 and J{sup PC} = 0{sup ++},2{sup ++} and 2{sup ++}, respectively, and can be considered as hadronic molecules made of D*D-bar*, D{sub s}*D-bar{sub s}*, decaying to a pair of light vectors, light-heavy vector or pseudoscalar-pseudoscalar.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2011

The scalar form factor and radius of the {sigma} resonance

We calculate the scalar form factor and the quadratic scalar radius of the {sigma} meson from Chiral Lagrangians. We also study the behavior of the Feynman-Hellman theorem for the mass of the {sigma}.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗