2
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Alioli S, Farina M, Pappadopulo D, Ruderman JT. Catching a New Force by the Tail. PHYSICAL REVIEW LETTERS 2018; 120:101801. [PMID: 29570328 DOI: 10.1103/physrevlett.120.101801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Indexed: 06/08/2023]
Abstract
The Large Hadron Collider (LHC) is sensitive to new heavy gauge bosons that produce narrow peaks in the dilepton invariant mass spectrum up to about m_{Z^{'}}∼5 TeV Z^{'}s that are too heavy to produce directly can reveal their presence through interference with standard model dilepton production. We show that the LHC can significantly extend the mass reach for such Z^{'}s by performing precision measurements of the shape of the dilepton invariant mass spectrum. The high-luminosity LHC can exclude, with 95% confidence, new gauge bosons as heavy as m_{Z^{'}}∼10-20 TeV that couple with gauge coupling strength of g_{Z^{'}}∼1-2.
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Affiliation(s)
- Simone Alioli
- CERN Theory Division, CH-1211, Geneva 23, Switzerland and Università degli Studi di Milano Bicocca, Piazza della Scienza 3, 20126 Milan, Italy
| | - Marco Farina
- New High Energy Theory Center, Department of Physics, Rutgers University, 136 Frelinghuisen Road, Piscataway, New Jersey 08854, USA
| | - Duccio Pappadopulo
- Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, New York 10003, USA
| | - Joshua T Ruderman
- Center for Cosmology and Particle Physics, Department of Physics, New York University, New York, New York 10003, USA
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3
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Schönherr M. An automated subtraction of NLO EW infrared divergences. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2018; 78:119. [PMID: 31258398 PMCID: PMC6560941 DOI: 10.1140/epjc/s10052-018-5600-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Accepted: 01/26/2018] [Indexed: 06/09/2023]
Abstract
In this paper a generalisation of the Catani-Seymour dipole subtraction method to next-to-leading order electroweak calculations is presented. All singularities due to photon and gluon radiation off both massless and massive partons in the presence of both massless and massive spectators are accounted for. Particular attention is paid to the simultaneous subtraction of singularities of both QCD and electroweak origin which are present in the next-to-leading order corrections to processes with more than one perturbative order contributing at Born level. Similarly, embedding non-dipole-like photon splittings in the dipole subtraction scheme discussed. The implementation of the formulated subtraction scheme in the framework of the Sherpa Monte-Carlo event generator, including the restriction of the dipole phase space through the α -parameters and expanding its existing subtraction for NLO QCD calculations, is detailed and numerous internal consistency checks validating the obtained results are presented.
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Affiliation(s)
- Marek Schönherr
- Theoretical Physics Department, CERN, 1211 Geneva 23, Switzerland
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4
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Forte S, Nisati A, Passarino G, Tenchini R, Calame CMC, Chiesa M, Cobal M, Corcella G, Degrassi G, Ferrera G, Magnea L, Maltoni F, Montagna G, Nason P, Nicrosini O, Oleari C, Piccinini F, Riva F, Vicini A. The Standard Model from LHC to future colliders. THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS 2015; 75:554. [PMID: 26692817 PMCID: PMC4665931 DOI: 10.1140/epjc/s10052-015-3759-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Accepted: 10/25/2015] [Indexed: 06/05/2023]
Abstract
This review summarizes the results of the activities which have taken place in 2014 within the Standard Model Working Group of the "What Next" Workshop organized by INFN, Italy. We present a framework, general questions, and some indications of possible answers on the main issue for Standard Model physics in the LHC era and in view of possible future accelerators.
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Affiliation(s)
- S. Forte
- />Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milan, Italy
- />INFN, Sezione di Milano, Via Celoria 16, 20133 Milan, Italy
| | - A. Nisati
- />INFN, Sezione di Roma, Piazzale Aldo Moro 2, 00185 Rome, Italy
| | - G. Passarino
- />Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, 10125 Turin, Italy
- />INFN, Sezione di Torino, Via P. Giuria 1, 10125 Turin, Italy
| | - R. Tenchini
- />INFN, Sezione di Pisa, Largo B. Pontecorvo 3, 56127 Pisa, Italy
| | | | - M. Chiesa
- />INFN, Sezione di Pavia, via Bassi 6, 27100 Pavia, Italy
| | - M. Cobal
- />Dipartimento di Chimica, Fisica e Ambiente, Università di Udine, Via delle Scienze, 206, 33100 Udine, Italy
- />INFN, Gruppo Collegato di Udine, Via delle Scienze, 206, 33100 Udine, Italy
| | - G. Corcella
- />INFN, Laboratori Nazionali di Frascati, Via E. Fermi 40, 00044 Frascati, Italy
| | - G. Degrassi
- />Dipartimento di Matematica e Fisica, Università’ Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy
- />INFN, Sezione di Roma Tre, Via della Vasca Navale 84, 00146 Rome, Italy
| | - G. Ferrera
- />Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milan, Italy
- />INFN, Sezione di Milano, Via Celoria 16, 20133 Milan, Italy
| | - L. Magnea
- />Dipartimento di Fisica, Università di Torino, Via P. Giuria 1, 10125 Turin, Italy
- />INFN, Sezione di Torino, Via P. Giuria 1, 10125 Turin, Italy
| | - F. Maltoni
- />Centre for Cosmology, Particle Physics and Phenomenology (CP3), Université Catholique de Louvain, 1348 Louvain-la-Neuve, Belgium
| | - G. Montagna
- />Dipartimento di Fisica, Università di Pavia, via Bassi 6, 27100 Pavia, Italy
- />INFN, Sezione di Pavia, via Bassi 6, 27100 Pavia, Italy
| | - P. Nason
- />INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, 20126 Milan, Italy
| | - O. Nicrosini
- />INFN, Sezione di Pavia, via Bassi 6, 27100 Pavia, Italy
| | - C. Oleari
- />Dipartimento di Fisica, Università di Milano-Bicocca, Piazza della Scienza 3, 20126 Milan, Italy
- />INFN, Sezione di Milano-Bicocca, Piazza della Scienza 3, 20126 Milan, Italy
| | - F. Piccinini
- />INFN, Sezione di Pavia, via Bassi 6, 27100 Pavia, Italy
| | - F. Riva
- />Institut de Théorie des Phénoménes Physiques, École Polytechnique Fédérale de Lausanne, 1015 Lausanne, Switzerland
| | - A. Vicini
- />Dipartimento di Fisica, Università di Milano, Via Celoria 16, 20133 Milan, Italy
- />INFN, Sezione di Milano, Via Celoria 16, 20133 Milan, Italy
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5
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Baumgart M, Rothstein IZ, Vaidya V. Calculating the annihilation rate of weakly interacting massive particles. PHYSICAL REVIEW LETTERS 2015; 114:211301. [PMID: 26066424 DOI: 10.1103/physrevlett.114.211301] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2014] [Indexed: 06/04/2023]
Abstract
We develop a formalism that allows one to systematically calculate the weakly interacting massive particle (WIMP) annihilation rate into gamma rays whose energy far exceeds the weak scale. A factorization theorem is presented which separates the radiative corrections stemming from initial-state potential interactions from loops involving the final state. This separation allows us to go beyond the fixed order calculation, which is polluted by large infrared logarithms. For the case of Majorana WIMPs transforming in the adjoint representation of SU(2), we present the result for the resummed rate at leading double-log accuracy in terms of two initial-state partial-wave matrix elements and one hard matching coefficient. For a given model, one may calculate the cross section by finding the tree level matching coefficient and determining the value of a local four-fermion operator. The effects of resummation can be as large as 100% for a 20 TeV WIMP. However, for lighter WIMP masses relevant for the thermal relic scenario, leading-log resummation modifies the Sudakov factors only at the 10% level. Furthermore, given comparably sized Sommerfeld factors, the total effect of radiative corrections on the semi-inclusive photon annihilation rate is found to be percent level. The generalization of the formalism to other types of WIMPs is discussed.
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Affiliation(s)
- Matthew Baumgart
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Ira Z Rothstein
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
| | - Varun Vaidya
- Department of Physics, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213, USA
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6
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Chiesa M, Montagna G, Barzè L, Moretti M, Nicrosini O, Piccinini F, Tramontano F. Electroweak Sudakov corrections to new physics searches at the LHC. PHYSICAL REVIEW LETTERS 2013; 111:121801. [PMID: 24093248 DOI: 10.1103/physrevlett.111.121801] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Indexed: 06/02/2023]
Abstract
We compute the one-loop electroweak Sudakov corrections to the production process Z(νν)+n jets, with n=1, 2, 3, in pp collisions at the LHC. It represents the main irreducible background to new physics searches at the energy frontier. The results are obtained at the leading and next-to-leading logarithmic accuracy by implementing the general algorithm of Denner and Pozzorini in the event generator for multiparton processes alpgen. For the standard selection cuts used by the ATLAS and CMS Collaborations, we show that the Sudakov corrections to the relevant observables can grow up to -40% at sqrt[s ]= 14 TeV. We also include the contribution due to undetected real radiation of massive gauge bosons, to show to what extent the partial cancellation with the large negative virtual corrections takes place in realistic event selections.
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Affiliation(s)
- Mauro Chiesa
- Dipartimento di Fisica, Università di Pavia, and INFN, Sezione di Pavia, Via A. Bassi 6, 27100 Pavia, Italy
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9
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Chiu JY, Golf F, Kelley R, Manohar AV. Electroweak Sudakov corrections using effective field theory. PHYSICAL REVIEW LETTERS 2008; 100:021802. [PMID: 18232855 DOI: 10.1103/physrevlett.100.021802] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Indexed: 05/25/2023]
Abstract
Electroweak Sudakov corrections of the form alphanlogms/MW,Z2 are summed using renormalization group evolution in soft-collinear effective theory. Results are given for the scalar, vector, and tensor form factors for fermion and scalar particles. The formalism for including massive gauge bosons in soft-collinear effective theory is developed.
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Affiliation(s)
- Jui-yu Chiu
- Department of Physics, University of California at San Diego, La Jolla, California 92093, USA
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10
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Ciafaloni M, Ciafaloni P, Comelli D. Towards collinear evolution equations in electroweak theory. PHYSICAL REVIEW LETTERS 2002; 88:102001. [PMID: 11909346 DOI: 10.1103/physrevlett.88.102001] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/09/2001] [Indexed: 05/23/2023]
Abstract
We investigate collinear factorization in electroweak radiative corrections to hard inclusive processes at the TeV scale. Because of the uncanceled double logs found previously, we find a factorization pattern which is qualitatively different from the analogous one in QCD. New types of splitting functions emerge which are needed to describe the initial beam charges and are dependent on an infrared cutoff provided by the symmetry breaking scale. We derive such splitting functions at the one-loop level for broken SU(2) gauge theory, and we also discuss the structure functions' evolution equations, under the assumption that isospin breaking terms are sufficiently subleading at higher orders.
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Affiliation(s)
- Marcello Ciafaloni
- Dipartimento di Fisica, Università di Firenze and INFN-Sezione di Firenze, via Sansone 1, I-50019 Sesto Fiorentino, Firenze, Italy
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11
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Ciafaloni M, Ciafaloni P, Comelli D. BLOCH-Nordsieck violation in spontaneously broken Abelian theories. PHYSICAL REVIEW LETTERS 2001; 87:211802. [PMID: 11736331 DOI: 10.1103/physrevlett.87.211802] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/04/2001] [Indexed: 05/23/2023]
Abstract
We point out that, in a spontaneously broken U(1) gauge theory, inclusive processes, whose primary particles are mass eigenstates that do not coincide with the gauge eigenstates, are not free of infrared logarithms. The charge mixing allowed by symmetry breaking and the ensuing Bloch-Nordsieck violation are here analyzed in a few relevant cases and in particular for processes initiated by longitudinal gauge bosons. Of particular interest is the example of weak hypercharge in the standard model where, in addition, left-right mixing effects arise in transversely polarized fermion beams.
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