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We present a new formalism for parton shower simulation of QCD jets, which incorporates the following features: invariance under boosts along jet axes, improved treatment of heavy quark fragmentation, angular-ordered evolution with soft…

High Energy Physics - Phenomenology · Physics 2014-11-17 Stefan Gieseke , Philip Stephens , Bryan Webber

We carry out extensive tests of the next-to-leading logarithmic (NLL) accuracy of the PanScales parton showers, as introduced recently for colour-singlet production in hadron collisions. The tests include comparisons to (semi-)analytic NLL…

High Energy Physics - Phenomenology · Physics 2022-11-23 Melissa van Beekveld , Silvia Ferrario Ravasio , Keith Hamilton , Gavin P. Salam , Alba Soto-Ontoso , Gregory Soyez , Rob Verheyen

The leptonic decays of the heavy gauge bosons W and/or Z provide a clear experimental signature at hadron colliders. The production of accompanying jets is an excellent signal to probe QCD, while also being the main background to many…

High Energy Physics - Phenomenology · Physics 2015-03-18 Flavia A. Dias , Emily Nurse , Gavin Hesketh

In this short note, I introduce to essential conceptual features and main building blocks of matrix element merging algorithms, operating on fixed order calculations both at leading order and next-to-leading order. The intention is purely…

High Energy Physics - Phenomenology · Physics 2015-03-30 Thomas Rössler

We motivate a measurement of various ratios of $W$ and $Z$ cross sections at the Large Hadron Collider (LHC) at large values of the boson transverse momentum ($p_T\gtrsim M_{W,Z}$). We study the dependence of predictions for these…

High Energy Physics - Phenomenology · Physics 2014-02-10 Sarah Alam Malik , Graeme Watt

Analysis of small-x semi-inclusive DIS hadroproduction suggests that multiple parton radiation leads to a broadening of transverse momentum distributions beyond that predicted by a straightforward calculation in the Collins-Soper-Sterman…

High Energy Physics - Phenomenology · Physics 2007-05-23 S. Berge , P. Nadolsky , F. Olness , C. -P. Yuan

Machine learning methods incorporating deep neural networks have been the subject of recent proposals for new hadronic resonance taggers. These methods require training on a dataset produced by an event generator where the true class labels…

High Energy Physics - Phenomenology · Physics 2017-01-25 James Barnard , Edmund Noel Dawe , Matthew J. Dolan , Nina Rajcic

This lecture discusses the physics implemented by Monte Carlo event generators for hadron colliders. It details the construction of parton showers and the matching of parton showers to fixed-order calculations at higher orders in…

High Energy Physics - Phenomenology · Physics 2015-06-19 Stefan Höche

We present pseudorapidity and transverse momentum distributions for the cross section for the production of the lightest neutral Higgs boson in association with a high-p_T hadronic jet, calculated in the framework of the minimal…

High Energy Physics - Phenomenology · Physics 2007-11-13 Oliver Brein , Wolfgang Hollik

We show the first results for parton distribution functions within the proton at the physical pion mass, employing the method of quasi-distributions. In particular, we present the matrix elements for the iso-vector combination of the…

We revisit the CKKW-L method for merging tree-level matrix elements with parton showers, and amend it with an add/subtract scheme to minimise dependencies on the merging scale. The scheme is constructed to, as far as possible, recover the…

High Energy Physics - Phenomenology · Physics 2015-06-12 Leif Lonnblad , Stefan Prestel

A factorization algorithm for a patron shower model based on the evolution of momentum distributions proposed in a previous work is studied. The scaling violation of initial state parton distributions is generated using parton showers to an…

High Energy Physics - Phenomenology · Physics 2008-11-26 Hidekazu Tanaka , Tetsuya Sugiura , Yuya Wakabayashi

We carry out a systematic classification and computation of next-to-leading order kinematic power corrections to the fully differential cross section in the parton shower. To do this we devise a map between ingredients in a parton shower…

High Energy Physics - Phenomenology · Physics 2011-02-18 Matthew Baumgart , Claudio Marcantonini , Iain W. Stewart

$W^+W^-\gamma$ production in proton-proton collision provides a window to the mechanism of electroweak symmetry breaking and a direct accessment to triple and quartic gauge couplings. Precision study of gauge boson self-interactions may…

High Energy Physics - Phenomenology · Physics 2020-05-22 Jian-Wen Zhu , Ren-You Zhang , Wen-Gan Ma , Qiang Yang , Yi Jiang

We provide the first theoretical study of a novel variable, $a_T$, proposed in Ref.[1] as a more accurate probe of the region of low transverse momentum $p_T$, for the $Z$ boson $p_T$ distribution at hadron colliders. The $a_T$ is the…

High Energy Physics - Phenomenology · Physics 2010-05-27 Andrea Banfi , Mrinal Dasgupta , Rosa Maria Duran Delgado

Jets serve as powerful tomographic probes of the quark-gluon plasma (QGP) created in relativistic heavy-ion collisions. While the expanding landscape of jet observables reveals multi-faceted aspects of jet-medium interactions, a precise and…

Nuclear Theory · Physics 2026-02-12 Yichao Dang , Wen-Jing Xing , Shanshan Cao , Guang-You Qin

Within perturbative QCD, we develop a new picture for the parton shower generated by a jet propagating through a dense quark-gluon plasma. This picture combines in a simple, factorised, way multiple medium-induced parton branchings and…

High Energy Physics - Phenomenology · Physics 2020-01-08 Paul Caucal , Edmond Iancu , Gregory Soyez

We present a process-independent technique to consistently combine next-to-leading order parton-level calculations of varying jet multiplicity and parton showers. Double counting is avoided by means of a modified truncated shower scheme.…

High Energy Physics - Phenomenology · Physics 2015-06-05 Stefan Hoeche , Frank Krauss , Marek Schonherr , Frank Siegert

Transverse momentum distribution of gauge bosons $W^{\pm}$ and $Z^0$ is calculated using unintegrated parton distributions obtained by solving leading order CCFM equation(s) in the impact parameter space. For illustration we compare the…

High Energy Physics - Phenomenology · Physics 2010-04-05 J. Kwiecinski , A. Szczurek

We perform calculations of Z+jet cross-section taking into account the transverse momenta of the initial partons. Transverse Momentum Dependent (TMD) parton densities obtained with the Parton Branching method are used and higher order…

High Energy Physics - Phenomenology · Physics 2019-05-15 M. Deak , A. van Hameren , H. Jung , A. Kusina , K. Kutak , M. Serino