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We use the infinite volume reconstruction method to calculate the charged/neutral pion mass difference. The hadronic tensor is calculated on lattice QCD and then combined with an analytic photon propagator, and the mass splitting is…

High Energy Physics - Lattice · Physics 2022-02-23 Xu Feng , Luchang Jin , Michael Joseph Riberdy

We discuss the end-point behavior of the pion distribution amplitude (DA) and calculate its slope using QCD sum rules with nonlocal condensates. This is done in terms of the standard derivative and also with the help of an "integral…

High Energy Physics - Phenomenology · Physics 2010-11-04 S. V. Mikhailov , A. V. Pimikov , N. G. Stefanis

We calculate the complete two-loop QCD amplitudes for hadronic $tW$ production by combining analytical and numerical techniques. The amplitudes have been first reduced to master integrals of eight planar and seven non-planar families, which…

High Energy Physics - Phenomenology · Physics 2023-08-02 Long-Bin Chen , Liang Dong , Hai Tao Li , Zhao Li , Jian Wang , Yefan Wang

We present a detailed investigation of the spacelike pion's electromagnetic form factor using three-point QCD sum rules that exclusively involve nonlocal condensates. Our main methodological tools are a spectral density which includes…

High Energy Physics - Phenomenology · Physics 2009-06-25 A. P. Bakulev , A. V. Pimikov , N. G. Stefanis

In this article, we will discuss geometric quantization of 2d QCD with fermionic and bosonic matter fields. We identify the respective large-N_c phase spaces as the infinite dimensional Grassmannian and the infinite dimensional Disc. The…

High Energy Physics - Theory · Physics 2009-10-30 S. G. Rajeev , O. T. Turgut

We evaluate the pion_0 into two gammas decay amplitude by an effective action derived from QCD in the quark composites approach, getting the standard value. We also verify that our effective action correctly reproduces the chiral anomaly.

High Energy Physics - Lattice · Physics 2007-05-23 Sergio Caracciolo , Fabrizio Palumbo

We consider the factorization properties of on-shell QCD amplitudes with massive partons in the limit when all kinematical invariants are large compared to the parton mass and discuss the structure of their infrared singularities. The…

High Energy Physics - Phenomenology · Physics 2009-01-07 S. Moch , A. Mitov

In order to directly compute physical two-pion K-decay amplitudes using lattice methods we must prepare a two-pion state with non-zero relative momentum. Building upon a proposal of Lellouch and L\"uscher, we describe a finite-volume method…

High Energy Physics - Lattice · Physics 2009-11-07 Changhoan Kim , Norman H. Christ

Two-dimensional QCD is studied from the point of view of existence of multiple chirally noninvariant solutions to the mass-gap equation. The ground-state solution is reproduced and an infinite set of replica solutions is discovered for this…

High Energy Physics - Phenomenology · Physics 2015-06-25 P. J. A. Bicudo , A. V. Nefediev

I review the status of the calculation of two-loop QCD corrections to non-leptonic B-decays in the framework of QCD factorisation. In the case of heavy-to-light decays I will cover the leading penguin amplitudes a_4^u and a_4^c. For…

High Energy Physics - Phenomenology · Physics 2014-10-15 Tobias Huber

We study 't Hooft's integral equation determining the meson masses M_n in multicolor QCD_2. In this note we concentrate on developing an analytic method, and restrict our attention to the special case of quark masses m_1=m_2=g/\sqrt{\pi}.…

High Energy Physics - Theory · Physics 2015-05-13 V. A. Fateev , S. L. Lukyanov , A. B. Zamolodchikov

Results for the equation of state in 2+1 flavor QCD at zero net baryon density using the Highly Improved Staggered Quark (HISQ) action by the HotQCD collaboration are presented. The strange quark mass was tuned to its physical value and the…

High Energy Physics - Lattice · Physics 2019-08-13 Tanmoy Bhattacharya

We discuss the QCD sum-rule approach for the spacelike electromagnetic pion form factor in the $O(\alpha_s)$ approximation. We show that the nonlocality of the condensates is a key point to include nonperturbative contributions to the pion…

High Energy Physics - Phenomenology · Physics 2010-02-18 Alexander P. Bakulev , A. V. Pimikov , N. G. Stefanis

In perturbation theory, the spectral densities of two-point functions develop non-integrable threshold singularities at higher orders. In QCD, such singularities emerge when calculating the diagrams in terms of the pole quark mass, and they…

High Energy Physics - Phenomenology · Physics 2021-01-20 Dmitri Melikhov , Silvano Simula

We investigate the interactions among the pion, vector mesons and external gauge fields in the holographic dual of massless QCD proposed in a previous paper, hep-th/0412141, on the basis of probe D8-branes embedded in a D4-brane background…

High Energy Physics - Theory · Physics 2008-11-26 Tadakatsu Sakai , Shigeki Sugimoto

We use QCD sum rules with nonlocal condensates to re-calculate more accurately the moments and their confidence intervals of the twist-2 pion distribution amplitude including radiative corrections. We are thus able to construct an…

High Energy Physics - Phenomenology · Physics 2009-11-07 A. P. Bakulev , S. V. Mikhailov , N. G. Stefanis

We analyze the spectrum of two- and three-pion states of maximal isospin obtained recently for isosymmetric QCD with pion mass $M\approx 200\;$MeV in Ref. [1]. Using the relativistic three-particle quantization condition, we find $\sim 2…

High Energy Physics - Lattice · Physics 2021-03-16 Tyler D. Blanton , Fernando Romero-López , Stephen R. Sharpe

In this work, we express the singular part of a scattering amplitude in terms of Feynman integrals compatible with topologies appearing in the bare amplitude, and we choose a basis of locally finite Master Integrals. In two-loop massless…

High Energy Physics - Phenomenology · Physics 2025-12-18 Piotr Bargiela

Recently, Kaplan proposed an interesting extension of QCD named Extended QCD or XQCD with bosonic auxiliary fields [1]. While its partition function is kept exactly the same as that of QCD, XQCD naturally contains properties of low-energy…

High Energy Physics - Lattice · Physics 2015-10-16 Hidenori Fukaya , Ryo Yamamura

We compute the complex, long-distance two-photon-exchange amplitude which contributes to the rare $K_{\rm L}\rightarrow\mu^+\mu^-$ decay from lattice QCD. We use a $24^3\times 64$ physical-pion-mass gauge field ensemble at an inverse…

High Energy Physics - Lattice · Physics 2025-11-06 Peter Boyle , En-Hung Chao , Norman Christ , Ceran Hu , Luchang Jin , Yidi Zhao