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We improve QCD calculations of the $B_{d, s} \to \pi, K$ form factors at large hadronic recoil by implementing the next-to-leading-logarithmic resummation for the obtained leading-power light-cone sum rules in the soft-collinear effective…

High Energy Physics - Phenomenology · Physics 2023-04-12 Bo-Yan Cui , Yong-Kang Huang , Yue-Long Shen , Chao Wang , Yu-Ming Wang

A recent study indicates that the $\alpha^2\alpha_s^2$ order QED processes of $\Upsilon \to \jpsi + X$ decay are compatible with those of QCD processes. However, in the endpoint region, the Non-relativistic QED (NRQED) calculation breaks…

High Energy Physics - Phenomenology · Physics 2015-05-14 Xiaohui Liu

We investigate the regularization-scheme dependence of scattering amplitudes in massless QCD and find that the four-dimensional helicity scheme (FDH) and dimensional reduction (DRED) are consistent at least up to NNLO in the perturbative…

High Energy Physics - Phenomenology · Physics 2016-02-17 A. Broggio , Ch. Gnendiger , A. Signer , D. Stöckinger , A. Visconti

We study the (exclusive) kT jet algorithm using effective field theory techniques. Regularizing the virtualities and rapidities of graphs in the soft-collinear effective theory (SCET), we are able to write the next-to-leading-order dijet…

High Energy Physics - Phenomenology · Physics 2012-04-20 William Man-Yin Cheung , Simon M. Freedman

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

We present predictions for the DIS 1-jettiness event shape $\tau_1^b$, or DIS thrust, using the framework of Soft Collinear Effective Theory (SCET) for factorization, resummation of large logarithms, and rigorous treatment of…

High Energy Physics - Phenomenology · Physics 2025-09-17 June-Haak Ee , Daekyoung Kang , Christopher Lee , Iain W. Stewart

Soft-collinear effective theory (SCET) is used to demonstrate factorization for event shape distributions in the two-jet region. The leading nonperturbative power corrections to these distributions can be characterized as shape functions…

High Energy Physics - Phenomenology · Physics 2008-11-26 Christopher Lee

We discuss restrictions on operators in the soft-collinear effective theory (SCET) which follow from the ambiguity in the decomposition of collinear momenta and the freedom in the choice of light-like basis vectors $n$ and $\bar n$.…

High Energy Physics - Phenomenology · Physics 2014-11-17 Aneesh V. Manohar , Thomas Mehen , Dan Pirjol , Iain W. Stewart

The effects of the soft gluon emission in hard scattering processes at the phase boundary are resummed in the soft-collinear effective theory (SCET). In SCET, the soft gluon emission is decoupled from the energetic collinear part, and is…

High Energy Physics - Phenomenology · Physics 2009-11-10 Junegone Chay , Chul Kim , Yeong Gyun Kim , Jong-Phil Lee

Soft-Collinear Effective Theory (SCET) has been formulated since a decade now in covariant gauges. In this work we derive a modified SCET Lagrangian applicable in both classes of gauges: regular and singular ones. This extends the range of…

High Energy Physics - Phenomenology · Physics 2011-08-08 Miguel Garcia-Echevarria , Ahmad Idilbi , Ignazio Scimemi

We compare threshold resummation in QCD, as performed using soft-collinear effective theory (SCET), to the standard perturbative QCD formalism based on factorization and resummation of Mellin moments of partonic cross-sections. We consider…

High Energy Physics - Phenomenology · Physics 2015-06-04 Marco Bonvini , Stefano Forte , Margherita Ghezzi , Giovanni Ridolfi

Matrix elements of Wilson-line dressed operators play a central role in the factorization of soft and collinear modes in gauge theories. When expressed using spinor helicity variables, these so-called form factors admit a classification…

High Energy Physics - Phenomenology · Physics 2024-06-07 Timothy Cohen , Marc Riembau

A complete basis for the next-to-next-to leading order heavy-to-light currents in the soft-collinear effective theory is constructed. Reparameterization invariance is imposed by deriving constraint equations. Their solutions give the set of…

High Energy Physics - Phenomenology · Physics 2013-05-29 Christian M. Arnesen , Joydip Kundu , Iain W. Stewart

Three-point correlators of spinning operators admit multiple tensor structures compatible with conformal symmetry. For conserved currents in three dimensions, we point out that helicity commutes with conformal transformations and we use…

High Energy Physics - Theory · Physics 2021-06-30 Simon Caron-Huot , Yue-Zhou Li

We present a systematic framework for the calculation of dijet soft functions, which are defined as a matrix element of two light-like Wilson lines that is weighted by a generic measurement function. Based on a universal parametrisation of…

High Energy Physics - Phenomenology · Physics 2015-12-21 Guido Bell , Rudi Rahn , Jim Talbert

The lightcone formalism including SU(3) breaking effects for the light pseudoscalar mesons is studied using soft-collinear effective theory (SCET), where the conformal symmetries needed for the expansion can be clearly implemented. The…

High Energy Physics - Phenomenology · Physics 2008-11-26 Chul Kim , Adam K. Leibovich

We describe in some detail the derivation of a power counting formula for the soft-collinear effective theory (SCET). This formula constrains which operators are required to correctly describe the infrared at any order in the Lambda_QCD/Q…

High Energy Physics - Phenomenology · Physics 2009-11-07 Christian W. Bauer , Dan Pirjol , Iain W. Stewart

These lectures provide an introduction to Soft-Collinear Effective Theory. As applications we discuss resummation for (i) soft-photon effects in QED, (ii) event-shape variables and (iii) jet cross sections.

High Energy Physics - Phenomenology · Physics 2018-03-13 Thomas Becher

We review progress in calculating one-loop scattering amplitudes required for next-to-leading-order corrections to QCD processes. The underlying technical developments include the spinor helicity formalism, color decompositions,…

High Energy Physics - Phenomenology · Physics 2010-11-15 Z. Bern , L. Dixon , D. A. Kosower

From a detailed analysis of cone-jet cross sections in effective field theory, we obtain novel factorization theorems which separate the physics associated with different energy scales present in such processes. The relevant low-energy…

High Energy Physics - Phenomenology · Physics 2017-05-08 Thomas Becher , Matthias Neubert , Lorena Rothen , Ding Yu Shao