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Related papers: RI'/SMOM scheme amplitudes for deep inelastic scat…

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We calculate the two-pion wave function for the I=2 $S$-wave two-pion system with a finite scattering momentum and estimate the interaction range between two pions. It allows us to examine the validity of the necessary condition for the…

High Energy Physics - Lattice · Physics 2008-11-26 Kiyoshi Sasaki , Naruhito Ishizuka

We propose a differential operator for computing the residues associated with a class of meromorphic $n$-forms that frequently appear in the Cachazo-He-Yuan form of the scattering amplitudes. This differential operator is conjectured to be…

High Energy Physics - Theory · Physics 2019-01-23 Gang Chen , Yeuk-Kwan E. Cheung , Tianheng Wang , Feng Xu

We perform a dedicated study of the $q \bar{q}$-initiated two-loop electroweak-QCD Drell-Yan scattering amplitude in dimensional regularization schemes for vanishing light quark and lepton masses. For the relative order $\alpha$ and…

High Energy Physics - Phenomenology · Physics 2023-01-11 Matthias Heller , Andreas von Manteuffel , Robert M. Schabinger , Hubert Spiesberger

We compute the scattering amplitude for Schr\"odinger operators at a critical energy level, corresponding to the maximum point of the potential. We follow the wrok of Robert and Tamura, '89, using Isozaki and Kitada's representation formula…

Analysis of PDEs · Mathematics 2007-05-23 Ivana Alexandrova , Jean-Francois Bony , Thierry Ramond

We calculate the renormalization constants (RCs) of vector, axial, vector scalar, pseudoscalar and tensor quark operators of the overlap valence fermion, on the 11 gauge ensembles with dynamical fermion using either Domain wall…

High Energy Physics - Lattice · Physics 2021-12-08 Fangcheng He , Yi-Bo Yang

We use massive spinor helicity formalism to study scattering amplitudes in $\mathcal{N}=2^*$ super-Yang-Mills theory in four dimensions. We compute the amplitudes at an arbitrary point in the Coulomb branch of this theory. We compute…

High Energy Physics - Theory · Physics 2022-08-15 Md. Abhishek , Subramanya Hegde , Dileep P. Jatkar , Arnab Priya Saha

The heavy quark effects in deep--inelastic scattering in the asymptotic regime $Q^2 \gg m^2$ can be described by heavy flavor operator matrix elements. Complete analytic expressions for these objects are currently known to ${\sf NLO}$. We…

High Energy Physics - Phenomenology · Physics 2009-06-25 I. Bierenbaum , J. Blümlein , S. Klein

We present and numerically implement a computational method to construct relativistic scattering amplitudes that obey analyticity, crossing, elastic and inelastic unitarity in three and four spacetime dimensions. The algorithm is based on…

High Energy Physics - Theory · Physics 2023-03-17 Piotr Tourkine , Alexander Zhiboedov

In the framework of light-cone QCD sum rules, we study the valence quark distribution function $q(x_B)$ of a pion for moderate $x_B$. The sum rule with the leading twist-2 wave function gives $q(x_B)=\varphi_\pi(x_B)$. Twist-4 wave…

High Energy Physics - Phenomenology · Physics 2007-05-23 V. M. Belyaev , Mikkel B. Johnson

Within the framework of large momentum effective theory (LaMET), the light-cone distribution amplitude of $B$-meson in heavy-quark effective theory (HQET) can be extracted from lattice calculations of quasidistribution amplitude through…

High Energy Physics - Phenomenology · Physics 2023-01-04 Ji Xu , Xi-Ruo Zhang

We introduce a new method for calculating the mixing matrix for non-singlet quark operators including total derivatives, based solely on their renormalization structure in the chiral limit. As input, the method requires the well-known…

High Energy Physics - Phenomenology · Physics 2022-03-02 Sam Van Thurenhout , Sven-Olaf Moch

A non perturbative computation of the evolution of singlet parton densities without gauge--fixing requires a gauge invariant gluon source operator. Within the Schr\"odinger Functional scheme (SF), such a source can be defined in terms of…

High Energy Physics - Lattice · Physics 2009-11-07 F. Palombi , R. Petronzio , A. Shindler

The low-energy spectrum and scattering of two-nucleon systems are studied with lattice quantum chromodynamics using a variational approach. A wide range of interpolating operators are used: dibaryon operators built from products of…

The quantum field theoretic treatment of inclusive deep--inelastic diffractive scattering given in a previous paper \cite{BGR2006} is discussed in detail using an equivalent formulation with the aim to derive a representation suitable for…

High Energy Physics - Phenomenology · Physics 2009-07-22 J. Blümlein , D. Robaschik , B. Geyer

The real-space multiple-scattering (RSMS) approach is applied to model non-resonant inelastic scattering from deep core electron levels over a broad energy spectrum. This approach is applicable to aperiodic or periodic systems alike and…

Other Condensed Matter · Physics 2009-11-11 J. A. Soininen , A. L. Ankudinov , J. J. Rehr

We compute the two-loop QCD helicity amplitudes for the process e^+e^- --> q bar{q} g. The amplitudes are extracted in a scheme-independent manner from the coefficients appearing in the general tensorial structure for this process. The…

High Energy Physics - Phenomenology · Physics 2010-04-06 L. W. Garland , T. Gehrmann , E. W. N. Glover , A. Koukoutsakis , E. Remiddi

Elastic nucleon-pion scattering amplitudes are computed using lattice QCD on a single ensemble of gauge field configurations with $N_{\rm f} = 2+1$ dynamical quark flavors and $m_{\pi} = 200~{\rm MeV}$. The $s$-wave scattering lengths with…

We discuss the calculation of two-loop helicity amplitudes for quark-quark scattering in QCD and four-gluino scattering in N=1 supersymmetric Yang-Mills theory. We study the dependence of the results on different variants of dimensional…

High Energy Physics - Phenomenology · Physics 2007-05-23 A. De Freitas , Z. Bern

We determine the low-energy behaviour of the scattering operator of two-dimensional Schr\"odinger operators with any type of obstructions at 0-energy. We also derive explicit formulas for the wave operators in the absence of p-resonances,…

Mathematical Physics · Physics 2021-09-01 Serge Richard , Rafael Tiedra de Aldecoa , Lyang Zhang

We describe a general method that enables us to obtain all the singular terms of helicity amplitudes of n-parton processes at one loop. The algorithm uses helicity amplitudes at tree level and simple color algebra. We illustrate the method…

High Energy Physics - Phenomenology · Physics 2009-10-28 Zoltan Kunszt , Adrian Signer , Zoltan Trocsanyi