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We present results for pion polarizabilities predicted using dispersion relations from our earlier Amplitude Analysis of world data on two photon production of meson pairs. The helicity-zero polarizabilities are rather stable and…

High Energy Physics - Phenomenology · Physics 2018-09-11 Ling-Yun Dai , Michael R. Pennington

We calculate the one--loop corrections to the Kroll--Ruderman low--energy theorems for charged pion photoproduction in the framework of heavy baryon chiral perturbation theory. We predict the threshold S--wave multipole $E_{0+}$ to be…

High Energy Physics - Phenomenology · Physics 2009-10-28 V. Bernard , N. Kaiser , Ulf-G. Meißner

The gluon polarisation in the nucleon has been determined by detecting charm production via D0 meson decay to charged K and pi in polarised muon scattering off a longitudinally polarised deuteron target. The data were taken by the COMPASS…

High Energy Physics - Experiment · Physics 2009-07-30 COMPASS Collaboration , M. Alekseev

The recently postulated existence of a baryon antidecuplet [1] can be reproduced in strong coupling theory in which a bare baryon spin 1/2 octet interacts with an octet of pseudoscalar mesons. When a suitable mixture of F- and D-type Yukawa…

High Energy Physics - Phenomenology · Physics 2007-05-23 C. Dullemond

Inclusive $H_b \to X_s \, \gamma$ decays, with $H_b$ a beauty baryon, are treated exploiting an expansion up to the third order in the inverse of the $b$ quark mass $m_b$ and to LO in $\alpha_s$, keeping the dependence on the hadron spin.…

High Energy Physics - Phenomenology · Physics 2024-10-10 Francesco Loparco

In this work, we investigate the chiral corrections to the magnetic moments of the spin-$3\over 2$ doubly charmed baryons systematically up to next-to-next-to-leading order with the heavy baryon chiral perturbation theory. The numerical…

High Energy Physics - Phenomenology · Physics 2018-06-08 Lu Meng , Hao-Song Li , Zhan-Wei Liu , Shi-Lin Zhu

We study Compton scattering in systems with A=1 and 2 using chiral perturbation theory up to fourth order. For the proton we fit the two undetermined parameters in the O(Q^4) $\gamma$p amplitude of McGovern to experimental data in the…

Nuclear Theory · Physics 2009-04-17 S. R. Beane , M. Malheiro , J. A. McGovern , D. R. Phillips , U. van Kolck

We present the tomographical structure of baryons by studying the nonforward matrix elements of lightlike correlation functions of the tensor current. At the leading twist, with the tensor current, four chiral-odd distributions are in…

High Energy Physics - Phenomenology · Physics 2026-01-30 Navpreet Kaur , Monika Randhawa , Harleen Dahiya

The differential cross sections for $\pi^- p \to \gamma n$ and $\pi^+ n \to \gamma p$ are computed up to $O(p^3)$ in heavy baryon chiral perturbation theory (HBChPT). The expressions at $O(p)$ and $O(p^2)$ have no free parameters. There are…

High Energy Physics - Phenomenology · Physics 2016-09-06 Harold W. Fearing , Thomas R. Hemmert , Randy Lewis , Christine Unkmeir

The complete analytical $O(m_l^3\alpha^5/m_p^2\times (\log{m_\pi}, \log{\Delta}, \log{m_l}))$ contribution to the Hyperfine splitting is given. It can explain about 2/3 of the difference between experiment and the pure QED prediction when…

High Energy Physics - Phenomenology · Physics 2007-05-23 Antonio Pineda

We calculate the parton distributions for both polarized and unpolarized octet and decuplet baryons, using the MIT bag, dressed by mesons. We show that the hyperfine interaction responsible for the $\Delta - N$ and $\Sigma^0 - \Lambda$…

High Energy Physics - Phenomenology · Physics 2010-02-17 C. Boros , A. W. Thomas

Understanding the origin and mechanism of the transverse polarization of hyperons produced in unpolarized proton-proton collision, $pp\to \Lambda^\uparrow X$, has been one of the long-standing issues in high-energy spin physics. In the…

High Energy Physics - Phenomenology · Physics 2021-09-29 Yuji Koike , Kenta Yabe , Shinsuke Yoshida

Manifestly Lorentz-invariant baryon chiral perturbation theory is used to calculate the radiative correction of low energy elastic lepton proton scatterings. Corrections of differential cross section and charge asymmetry are given at chiral…

High Energy Physics - Phenomenology · Physics 2022-05-16 Xiong-Hui Cao , Qu-Zhi Li , Han-Qing Zheng

We report on the calculation of the CP-violating form factor $F_3$ and the corresponding electric dipole moment for charmed baryons in the spin-1/2 sector generated by the QCD $\theta$-term. We work in the framework of covariant baryon…

High Energy Physics - Phenomenology · Physics 2021-02-03 Y. Ünal , Ulf-G. Meißner

We review the calculation of suppression of Chiral Separational and Chiral Vortical Effects for strange quarks (which allegedly yield spin polarization of $\Lambda/\bar\Lambda$-hyperons in peripheral Heavy-Ion Collisions) by the…

High Energy Physics - Phenomenology · Physics 2024-11-21 Ruslan A. Abramchuk

We compute the transverse single spin asymmetry in light hadron production $p^\uparrow p\to hX$ and $p^\uparrow A\to hX$ including the gluon saturation effect in the unpolarized nucleon/nucleus. In the forward (large-$x_F$) region, the…

High Energy Physics - Phenomenology · Physics 2016-09-21 Yoshitaka Hatta , Bo-Wen Xiao , Shinsuke Yoshida , Feng Yuan

We study the chiral loop corrections to the generalized Gerasimov-Drell-Hearn sum rule of the nucleon for finite photon virtuality in the framework of a Lorentz-invariant formulation of baryon chiral perturbation theory. We perform a…

High Energy Physics - Phenomenology · Physics 2009-11-07 Véronique Bernard , Thomas R. Hemmert , Ulf-G. Meißner

The masses of the charmed baryons in the ${\bf 6}$ representation of $SU(3)$ obey an equal spacing rule at lowest order in $SU(3)$ breaking, ${\cal O}(m_s)$. We compute the corrections to this relation at order ${\cal O}(m_s^{3/2})$ arising…

High Energy Physics - Phenomenology · Physics 2009-10-28 Martin J. Savage

The effect of $\Sigma^*(1385)$ baryon resonance on the time evolution of the $\Lambda$ hyperon polarization in hadronic matter is studied using a kinetic approach. This approach explicitly includes the production of the $\Sigma^*$ resonance…

Nuclear Theory · Physics 2026-01-19 Haesom Sung , Che Ming Ko , Su Houng Lee

We perform a chiral extrapolation of the baryon octet and decuplet masses in a relativistic formulation of chiral perturbation theory. A partial summation is assumed as implied by the use of physical baryon and meson masses in the one-loop…

High Energy Physics - Phenomenology · Physics 2015-06-03 A. Semke , M. F. M. Lutz