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Related papers: BELLE Data on the $\pi^0 \gamma* \gamma$ Form Fact…

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The gamma^* --> gamma pi^0 transition measured at different photon virtualities already provides us with a clean test for the behaviour of the pi^0 gamma^* gamma off-shell axial anomaly at large time-like squared momenta. It also allows…

High Energy Physics - Phenomenology · Physics 2014-11-17 J. -M. Gerard , G. Lopez Castro

We analyze the time-like processes gamma gamma -> B Bbar and p p-bar -> gamma M at large Mandelstam variables within the handbag approach for which the process amplitudes factorize in hard partonic subprocesses and annihilation form factor.…

High Energy Physics - Phenomenology · Physics 2013-11-05 P. Kroll , A. Schaefer

We update the theoretical framework for the QCD calculation of transition form factors $\gamma^*\gamma\to\eta$ and $\gamma^*\gamma\to\eta'$ at large photon virtualities including full next-to-leading order analysis of perturbative…

High Energy Physics - Phenomenology · Physics 2014-10-22 S. S. Agaev , V. M. Braun , N. Offen , F. A. Porkert , A. Schäfer

We investigate the form factors for pseudoscalar-meson-photon transitions by means of dispersive QCD sum rules and demonstrate that most of the measurements done so far (in particular, those by BaBar for $\eta,$ $\eta',$ and $\eta_c$ and…

High Energy Physics - Phenomenology · Physics 2014-04-15 Wolfgang Lucha , Dmitri Melikhov

Using the CLEO~II detector, we have measured the differential cross sections for exclusive two-photon production of light pseudoscalar mesons $\pi^0$, $\eta$, and $\eta^{\prime}$. From our measurements we have obtained the form factors…

High Energy Physics - Experiment · Physics 2010-04-08 CLEO Collaboration , J. Gronberg et al

We present measurements of the gamma gamma* --> pi0 transition form factor for the momentum transfer range Q^2=4-40 GeV^2 and the gamma gamma* --> eta_c transition form factor for the range Q^2=2-50 GeV^2. The results of the measurement of…

High Energy Physics - Experiment · Physics 2014-11-20 V. P. Druzhinin

A state-of-the-art analysis of the pion-photon transition form factor is presented based on an improved theoretical calculation that includes the effect of a finite virtuality of the quasi-real photon in the method of light-cone sum rules.…

High Energy Physics - Phenomenology · Physics 2013-05-31 N. G. Stefanis , A. P. Bakulev , S. V. Mikhailov , A. V. Pimikov

The behavior of the $\bpi$ form factors in the entire physical range is examined in a model independent way. Unitarity bounds are further constrained by the lattice results (APE). From this analysis, we obtain $f^{+}(0) = 0.38 \pm .03$ if…

High Energy Physics - Phenomenology · Physics 2016-09-01 Damir Becirevic

The form factors for the $B-->\pi$ transition are evaluated in the entire momentum transfer range by using the constraints obtained in the framework combining the heavy quark expansion and chiral symmetry for light quarks and the quark…

High Energy Physics - Phenomenology · Physics 2009-10-31 Riazuddin , T. A. Al-Aithan , Amjad Hussain Shah Gilani

We present the status of recent results from the BaBar and Belle experiments on the measurement of the angle gamma from the Dalitz plot analyses of B0->Kspi+pi- and B0->K+pi-pi0.

High Energy Physics - Experiment · Physics 2015-03-17 Eugenia Maria Teresa Irene Puccio

We review the observational information on the constancy of the fine structure constant alpha. We find that small improvements on the measurement of ^{187}Re lifetime can provide significant progress in exploring the range of variability…

Astrophysics · Physics 2009-11-07 G. Fiorentini , B. Ricci

The $\gamma^\ast \gamma \to \pi^0$ transition form factor, $G(Q^2)$, is computed on the entire domain of spacelike momenta using a continuum approach to the two valence-body bound-state problem in relativistic quantum field theory: the…

Using a continuum approach to the hadron bound-state problem, we calculate $\gamma^\ast \gamma \to \eta, \eta^\prime$ transition form factors on the entire domain of spacelike momenta, for comparison with existing experiments and in…

A simple method is used to extrapolate the form factor for the process gamma* gamma *--->pi^0 when two virtual photons produce a pi ^0 from the region of large spacelike photon virtualities to the experimentally accessible case when one of…

High Energy Physics - Phenomenology · Physics 2009-10-31 N. Nasrallah

We have used the PIBETA large acceptance detector for a precise measurement of the $\pi^+ \to e^+\nu\gamma$ radiative decay at rest, with broad phase space coverage. Using the CVC value for the pion vector form factor, $F_V = 0.0259(5)$, we…

High Energy Physics - Experiment · Physics 2019-08-14 Dinko Pocanic

We study the transition form factors of the pesudoscalar mesons ($\pi,\eta$ and $\eta^{\prime}$) as functions of the momentum transfer $Q^2$ within the light-front quark model. We compare our results with the recent experimental data by…

High Energy Physics - Phenomenology · Physics 2015-06-11 Chao-Qiang Geng , Chong-Chung Lih

In view of future plans for accurate measurements of the theoretically clean branching ratios Br(K+ -> pi+ nu nu) and Br(KL -> pi0 nu nu), that should take place in the next decade, we collect the relevant formulae for quantities of…

High Energy Physics - Phenomenology · Physics 2009-09-29 Andrzej J. Buras , Felix Schwab , Selma Uhlig

We discuss the latest results and future prospects of the Belle experiment on the electroweak and radiative processes b --> s ell+ ell-, b --> s gamma and b --> d gamma. In particular, the first measurement of the inclusive rate for B -->…

High Energy Physics - Experiment · Physics 2007-05-23 M. Nakao

A consistent treatment of $B\rightarrow \pi l \nu$ decay is given on the light-front. The $B$ to $\pi$ transition form factors are calculated in the entire physical range of momentum transfer for the first time. The valence-quark…

High Energy Physics - Phenomenology · Physics 2010-11-19 C. Y. Cheung , C. W. Hwang , W. M. Zhang