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Related papers: Charge asymmetries in e+e- -> pi+ pi- gamma at the…

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The physical state of $\rho$-$\omega$-$\phi$ mesons can be mixed by the unitary matrix. The decay processes of $\omega \rightarrow \pi^{+}\pi^{-}$ and $\phi \rightarrow \pi^{+}\pi^{-}$ are from the isospin symmetry breaking. The…

High Energy Physics - Phenomenology · Physics 2022-11-09 Gang Lü , Yan-Lin Zhao , Liang-Chen Liu , Xin-Heng Guo

It is shown that in reaction \gamma\gamma\to\ell^+\ell^-+\nu's at \sqrt{s}>200 GeV with polarized photons, large and well observable differences arise in the distribution of positive and negative charged leptons (\ell=\mu^\pm, e^\pm),…

High Energy Physics - Phenomenology · Physics 2009-02-23 D. A. Anipko , M. Cannoni , I. F. Ginzburg , K. A. Kanishev , A. V. Pak , O. Panella

In view of ongoing experimental activities to determine the pion polarizabilities, we have started to recalculate the available two-loop expressions in the framework of chiral perturbation theory, because they have never been checked…

High Energy Physics - Phenomenology · Physics 2008-11-26 Juerg Gasser , Mikhail A. Ivanov , Mikko E. Sainio

We measured, with the KLOE detector, the spectrum of pi+pi- invariant mass in a sample of 6.7 x 10^5 e+e- --> pi+pi-g events with the photon at large polar angle (theta_g>45^o) at a centre of mass energy sqrt(s) around the phi mass. We…

High Energy Physics - Experiment · Physics 2012-08-27 KLOE collaboration

A review on the requirements of chiral symmetry on effective quark models is presented. The connection between the pion Salpeter amplitude and the mass gap equation is discussed. Hadronic scattering, notably, $\pi\pi$ scattering is…

High Energy Physics - Phenomenology · Physics 2007-05-23 J. E. Ribeiro

A consistent treatment of the ground state correlations beyond the random phase approximation including their influence on the pairing and phonon-phonon coupling in nuclei is presented. A new general system of nonlinear equations for the…

Nuclear Theory · Physics 2007-05-23 A. P. Severyukhin , V. V. Voronov , D. Karadjov

We calculate the isospin symmetry violating effects to the reactions $pp\rightarrow d\pi ^+$ and $np\rightarrow d\pi ^0$ arising from the different hadron masses and from the Coulomb interaction between the positive pion and the deuteron.…

Nuclear Theory · Physics 2009-10-30 J. A. Niskanen , M. Vestama

Within the framework of dispersion theory, we study the the processes $e^+e^-\to \phi(2170) \to \phi \pi\pi(K\bar{K})$. The strong pion-pion final-state interactions, especially the $K\bar{K}$ coupled channel in the $S$-wave, are taken into…

High Energy Physics - Phenomenology · Physics 2023-07-11 Yun-Hua Chen

The complementarity between Chiral Perturbation Theory and the Linear Sigma Model in the scalar channel is exploited to study $\pi^0\pi^0$ production in $\rho$ and $\omega$ radiative decays, where the effects of a low mass scalar resonance…

High Energy Physics - Phenomenology · Physics 2009-09-24 A. Bramon , R. Escribano , J. L. Lucio M. , M. Napsuciale

We construct effective one-loop vertices and propagators in the linear sigma model at finite temperature, satisfying the chiral Ward identities and thus respecting chiral symmetry, treating the pion momentum, pion mass and temperature as…

High Energy Physics - Phenomenology · Physics 2009-10-31 Alejandro Ayala , Sarira Sahu

The various dynamical scales below the pion mass involved in $\pi^{+}$ $\pi^{-}$ atoms are sequentially integrated out using non-relativistic effective field theory techniques. This allows us to systematically organise the corrections to…

High Energy Physics - Phenomenology · Physics 2009-10-31 D. Eiras , J. Soto

We present a calculation of the pi+ pi- invariant-mass correlations and the pion balance functions in the single-freeze-out model. A satisfactory agreement with the data for Au+Au collisions is found.

Nuclear Theory · Physics 2009-11-10 W. Florkowski , W. Broniowski , P. Bozek

The process eta -> pi0 pi0 gamma gamma is discussed in Chiral Perturbation Theory (ChPT) extending two recent analyses. Special attention is devoted to one-loop corrections, eta-eta' mixing effects and vector-meson dominance of ChPT…

High Energy Physics - Phenomenology · Physics 2009-10-30 Ll. Ametller , J. Bijnens , A. Bramon , P. Talavera

Beam asymmetries for the reactions gamma p -> p pi0 and gamma p -> n pi+ have been measured with the CEBAF Large Acceptance Spectrometer (CLAS) and a tagged, linearly polarized photon beam with energies from 1.102 to 1.862 GeV. A Fourier…

Nuclear Experiment · Physics 2015-06-16 M. Dugger , B. G. Ritchie , P. Collins , E. Pasyuk , W. J. Briscoe , I. I. Strakovsky , R. L. Workman , Y. Azimov

We present a summary of measurements sensitive to the CKM angle \phi 2 (\alpha), performed by the BaBar and the Belle experiments which both collect B\bar{B} pairs produced at the \Upsilon(4S) resonance in asymmetric e+e- collisions. We…

High Energy Physics - Experiment · Physics 2013-07-31 Pit Vanhoefer

The problem of Gamma + Pi --> Pi + Pi is studied using the axial anomaly, elastic unitarity, analyticity and crossing symmetry. Single variable dispersion relation is assumed. Using elastic unitarity relation, an integral equation equation…

High Energy Physics - Phenomenology · Physics 2007-05-23 Tran N. Truong

Leading-order electromagnetic loop corrections to the one-pion-exchange potential are computed within the framework of chiral perturbation theory. These corrections generate an effective nucleon-nucleon potential, $V_{\pi \gamma}$, which…

Nuclear Theory · Physics 2008-11-26 U. van Kolck , M. C. M. Rentmeester , J. L. Friar , T. Goldman , J. J. de Swart

The e+e- --> pi+pi-pi0pi0 reaction cross section as a function of the incident energy is calculated using a model that is an extension of our recently published model of the e+e- annihilation into four charged pions. The latter considered…

High Energy Physics - Phenomenology · Physics 2008-11-26 Josef Juran , Peter Lichard

We study the effect of the sigma(600) and a_1(1260) resonances in the rho^0 -> pi^+ pi^- gamma decay, within the meson dominance model. Major effects are driven by the mass and width parameters of the sigma(600), and the usually neglected…

High Energy Physics - Phenomenology · Physics 2008-11-26 G. Toledo Sanchez , J. L. Garcia-Luna , V. Gonzalez-Enciso

We consider the interference of resonant amplitudes leading to the final state $K_S \pi^+ \pi^-$ in $D^0/\bar {D^0}$ decays. Each of these amplitudes consists of both Cabibbo allowed and doubly Cabibbo suppressed transitions. The role of…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Arunagiri