Publications by Gavin Salam


Phenomenology of event shapes at hadron colliders

JOURNAL OF HIGH ENERGY PHYSICS (2010) ARTN 038

A Banfi, GP Salam, G Zanderighi


A posteriori inclusion of parton density functions in NLO QCD final-state calculations at hadron colliders: the APPLGRID project

European Physical Journal C Springer Verlag 66 (2010) 503-524

T Carli>, D Clements, A Cooper-Sarkar, C Gwenlan, GP Salam, F Siegert, P Starovoitov, M Sutton

A method to facilitate the consistent inclusion of cross-section measurements based on complex final-states from HERA, TEVATRON and the LHC in proton parton density function (PDF) fits has been developed. This can be used to increase the sensitivity of LHC data to deviations from Standard Model predictions. The method stores perturbative coefficients of NLO QCD calculations of final-state observables measured in hadron colliders in look-up tables. This allows the a posteriori inclusion of parton density functions (PDFs), and of the strong coupling, as well as the a posteriori variation of the renormalisation and factorisation scales in cross-section calculations. The main novelties in comparison to original work on the subject are the use of higher-order interpolation of Lagrangian form, which substantially improves the trade-off between accuracy and memory use, and a CPU and computer memory optimised way to construct and store the look-up table using modern software tools. It is demonstrated that a sufficient accuracy on the cross-section calculation can be achieved with reasonably small look-up table size by using the examples of jet production and electro-weak boson (Z, W) production in proton-proton collisions at a center-of-mass energy of 14 TeV at the LHC. The use of this technique in PDF fitting is demonstrated in a PDF-fit to HERA data and simulated LHC jet cross-sections as well as in a study of the jet cross-section uncertainties at various centre-of-mass energies. © Springer-Verlag / Società Italiana di Fisica 2010


On the characterisation of the underlying event

JOURNAL OF HIGH ENERGY PHYSICS (2010) ARTN 065

M Cacciari, GP Salam, S Sapeta


Fat jets for a light higgs boson.

Physical review letters 104 (2010) 111801-

T Plehn, GP Salam, M Spannowsky

At the LHC associated top quark and Higgs boson production with a Higgs boson decay to bottom quarks has long been a heavily disputed search channel. Recently, it has been found not to be viable. We show how it can be observed by tagging massive Higgs bosons and top jets. For this purpose we construct boosted top and Higgs taggers for standard-model processes in a complex QCD environment.


Discovering baryon-number violating neutralino decays at the LHC.

Physical review letters 103 (2009) 241803-

JM Butterworth, JR Ellis, AR Raklev, GP Salam

Recently there has been much interest in the use of single-jet mass and jet substructure to identify boosted particles decaying hadronically at the LHC. We develop these ideas to address the challenging case of a neutralino decaying to three quarks in models with baryonic violation of R parity. These decays have previously been found to be swamped by QCD backgrounds. We demonstrate for the first time that such a decay might be observed directly at the LHC with high significance, by exploiting characteristics of the scales at which its composite jet breaks up into subjets.


A Higher Order Perturbative Parton Evolution Toolkit (HOPPET)

COMPUTER PHYSICS COMMUNICATIONS 180 (2009) 120-156

GP Salam, J Rojo


What HERA may provide?

DIS 2008 - Proceedings of the 16th International Workshop on Deep-Inelastic Scattering and Related Topics (2008)

H Jung, A De Roeck, J Bartels, O Behnke, J Blümlein, S Brodsky, A Cooper-Sarkar, M Deák, R Devenish, M Diehl, T Gehrmann, G Grindhammer, G Gustafson, V Khoze, A Knutsson, M Klein, F Krauss, K Kutak, E Laenen, L Lönnblad, L Motyka, PR Newman, F Olness, D Pitzl, M Ruspa, AS Vera, GP Salam, T Schörner-Sadenius, M Strikman

More than 100 people participated in a discussion session at the DIS08 workshop on the topic What HERA may provide. A summary of the discussion with a structured outlook and list of desirable measurements and theory calculations is given.


Quantifying the performance of jet definitions for kinematic reconstruction at the LHC

JOURNAL OF HIGH ENERGY PHYSICS (2008) ARTN 032

M Cacciari, J Rojo, GP Salam, G Soyez


Traveling waves and impact-parameter correlations

PHYSICAL REVIEW D 78 (2008) ARTN 054009

S Munier, GP Salam, G Soyez


Jet substructure as a new Higgs-search channel at the Large Hadron Collider.

Physical review letters 100 (2008) 242001-

JM Butterworth, AR Davison, M Rubin, GP Salam

It is widely considered that, for Higgs boson searches at the CERN Large Hadron Colider, WH and ZH production where the Higgs boson decays to bb are poor search channels due to large backgrounds. We show that at high transverse momenta, employing state-of-the-art jet reconstruction and decomposition techniques, these processes can be recovered as promising search channels for the standard model Higgs boson around 120 GeV in mass.


The catchment area of jets

JOURNAL OF HIGH ENERGY PHYSICS (2008) ARTN 005

M Cacciari, GP Salam, G Soyez


The anti-k(t) jet clustering algorithm

JOURNAL OF HIGH ENERGY PHYSICS (2008) ARTN 063

M Cacciari, GP Salam, G Soyez


Non-perturbative QCD effects in jets at hadron colliders

JOURNAL OF HIGH ENERGY PHYSICS (2008) ARTN 055

M Dasgupta, L Magnea, GP Salam


Pileup subtraction using jet areas

PHYSICS LETTERS B 659 (2008) 119-126

M Cacciari, GP Salam


The HOPPET NNLO parton evolution package

Proceedings of the XVI International Workshop on Deep-Inelastic Scattering and Related Topics Science Wise Publishing (2008)

J Rojo, G Salam


Jet substructure as a new Higgs search channel at the LHC

SUPERSYMMETRY AND THE UNIFICATION OF FUNDAMENTAL INTERACTIONS 1078 (2008) 189-+

JM Butterworth, AR Davison, M Rubin, GP Salam


A matrix formulation for small-x singlet evolution

JOURNAL OF HIGH ENERGY PHYSICS (2007) ARTN 046

M Ciafaloni, D Colferai, GP Salam, AM Stasto


Accurate QCD predictions for heavy-quark jets at the Tevatron and LHC

JOURNAL OF HIGH ENERGY PHYSICS (2007) ARTN 026

A Banfi, GP Salam, G Zanderighi


Accurate QCD predictions for heavy-quark jets at the Tevatron and LHC

Journal of High Energy Physics 2007 (2007)

A Banfi, GP Salam, G Zanderighi

Heavy-quark jets are important in many of today's collider studies and searches, yet predictions for them are subject to much larger uncertainties than for light jets. This is because of strong enhancements in higher orders from large logarithms, ln(pt/mQ). We propose a new definition of heavy-quark jets, which is free of final-state logarithms to all orders and such that all initial-state collinear logarithms can be resummed into the heavy-quark parton distributions. Heavy-jet spectra can then be calculated in the massless approximation, which is simpler than a massive calculation and reduces the theoretical uncertainties by a factor of three. This provides the first ever accurate predictions for inclusive b- and c-jets, and the latter have significant discriminatory power for the intrinsic charm content of the proton. The techniques introduced here could be used to obtain heavy-flavour jet results from existing massless next-to-leading order calculations for a wide range of processes. We also discuss the experimental applicability of our flavoured jet definition. © SISSA 2007.


A practical seedless infrared-safe cone jet algorithm

JOURNAL OF HIGH ENERGY PHYSICS (2007) ARTN 086

GP Salam, G Soyez

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