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TH Articles

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2017-04-13
08:29
Single top polarisation as a window to new physics / Aguilar-Saavedra, J.A. (Granada U., Theor. Phys. Astrophys.) ; Degrande, C. (CERN) ; Khatibi, S. (IPM, Tehran)
We discuss the effect of heavy new physics, parameterised in terms of four-fermion operators, in the polarisation of single top (anti-)quarks in the $t$-channel process at the LHC. It is found that for operators involving a right-handed top quark field the relative effect on the longitudinal polarisation is twice larger than the relative effect on the total cross section. [...]
CERN-TH-2017-013; arXiv:1701.05900.- 2017 - 9 p. - Published in : 10.1016/j.physletb.2017.04.023 Article from SCOAP3: PDF; Elsevier Open Access article: PDF; Fulltext: PDF;

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2017-04-12
07:18
Colorful Twisted Top Partners and Partnerium at the LHC / Kats, Yevgeny (CERN ; Ben Gurion U. of Negev ; Weizmann Inst.) ; McCullough, Matthew (CERN) ; Perez, Gilad (Weizmann Inst.) ; Soreq, Yotam (MIT, Cambridge, CTP) ; Thaler, Jesse (MIT, Cambridge, CTP)
In scenarios that stabilize the electroweak scale, the top quark is typically accompanied by partner particles. In this work, we demonstrate how extended stabilizing symmetries can yield scalar or fermionic top partners that transform as ordinary color triplets but carry exotic electric charges. [...]
MIT-CTP-4897; CERN-TH-2017-073; arXiv:1704.03393.- 2017-06-23 - 38 p. - Published in : JHEP 1706 (2017) 126 Fulltext: PDF;

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2017-04-07
07:44
Long-range critical exponents near the short-range crossover / Behan, Connor (YITP, Stony Brook) ; Rastelli, Leonardo (YITP, Stony Brook) ; Rychkov, Slava (CERN ; Ecole Normale Superieure ; UPMC, Paris (main)) ; Zan, Bernardo (ITPP, Lausanne ; CERN)
The $d$-dimensional long-range Ising model, defined by spin-spin interactions decaying with the distance as the power $1/r^{d+s}$, admits a second order phase transition with continuously varying critical exponents. At $s = s_*$, the phase transition crosses over to the usual short-range universality class. [...]
YITP-SB-17-12; CERN-TH-2017-058; arXiv:1703.03430.- 2017-06-15 - 5 p. - Published in : Phys. Rev. Lett. 118 (2017) 241601 Fulltext: PDF;

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2017-03-30
07:24
$W^\pm Z$ production at the LHC: fiducial cross sections and distributions in NNLO QCD / Grazzini, Massimiliano (Zurich U.) ; Kallweit, Stefan (CERN) ; Rathlev, Dirk (Zurich U.) ; Wiesemann, Marius (Zurich U. ; CERN)
We report on the first fully differential calculation for $W^\pm Z$ production in hadron collisions up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. Leptonic decays of the $W$ and $Z$ bosons are consistently taken into account, i.e. [...]
ZU-TH-06-17; CERN-TH-2017-065; arXiv:1703.09065.- 2017-03-27 - 38 p. - Published in : JHEP 05 (2017) 139 Fulltext: PDF;

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2017-03-30
07:23
Inflationary Perturbations in No-Scale Theories / Salvio, Alberto (CERN)
We study the inflationary perturbations in general (classically) scale-invariant theories. Such scenario is motivated by the hierarchy problem and provides natural inflationary potentials and dark matter candidates. [...]
CERN-TH-2017-068; arXiv:1703.08012.- 2017-03-23 - 38 p. - Published in : Eur. Phys. J. C 77 (2017) 267 Fulltext: PDF; Springer Open Access article: PDF;

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2017-03-30
07:22
Right-handed charged currents in the era of the Large Hadron Collider / Alioli, S. (CERN) ; Cirigliano, V. (Los Alamos Natl. Lab., Theor. Div.) ; Dekens, W. (Los Alamos Natl. Lab., Theor. Div. ; New Mexico Consortium, Los Alamos) ; de Vries, J. (NIKHEF, Amsterdam) ; Mereghetti, E. (Los Alamos Natl. Lab., Theor. Div.)
We discuss the phenomenology of right-handed charged currents in the framework of the Standard Model Effective Field Theory, in which they arise due to a single gauge-invariant dimension-six operator. We study the manifestations of the nine complex couplings of the $W$ to right-handed quarks in collider physics, flavor physics, and low-energy precision measurements. [...]
CERN-TH-2017-043; LA-UR-17-21898; NIKHEF-2017-014; arXiv:1703.04751.- 2017-03-14 - 50 p. - Published in : JHEP 05 (2017) 086 Fulltext: PDF;

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2017-03-14
16:44
SMD-based numerical stochastic perturbation theory / Dalla Brida, Mattia (Milan Bicocca U. ; INFN, Milan Bicocca) ; Lüscher, Martin (CERN ; Bern U.)
The viability of a variant of numerical stochastic perturbation theory, where the Langevin equation is replaced by the SMD algorithm, is examined. In particular, the convergence of the process to a unique stationary state is rigorously established and the use of higher-order symplectic integration schemes is shown to be highly profitable in this context. [...]
CERN-TH-2017-057; arXiv:1703.04396.- 2017 - 35 p. - Published in : Eur. Phys. J. C 77 (2017) 308 Fulltext: PDF; Springer Open Access article: PDF;

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2017-03-14
16:44
Dispersion relation for hadronic light-by-light scattering: two-pion contributions / Colangelo, Gilberto (Bern U. ; U. Bern, AEC) ; Hoferichter, Martin (Washington U., Seattle ; Santa Barbara, KITP) ; Procura, Massimiliano (CERN) ; Stoffer, Peter (Bonn U., HISKP ; U. Bonn, Phys. Inst., BCTP ; UC, San Diego)
In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic moment of the muon $(g-2)_\mu$, including a detailed discussion of the unitarity relation for arbitrary partial waves. We show that obtaining a final expression free from unphysical helicity partial waves is a subtle issue, which we thoroughly clarify. [...]
INT-PUB-17-009; CERN-TH-2017-041; NSF-KITP-17-036; arXiv:1702.07347.- 2017 - 70 p. - Published in : JHEP 04 (2017) 161 Fulltext: PDF; Springer Open Access article: PDF;

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2017-03-14
16:44
Cuts from residues: the one-loop case / Abreu, Samuel (Freiburg U.) ; Britto, Ruth (Trinity Coll., Dublin ; IPhT, Saclay) ; Duhr, Claude (CERN ; Louvain U., CP3) ; Gardi, Einan (U. Edinburgh, Higgs Ctr. Theor. Phys. ; Edinburgh U.)
Using the multivariate residue calculus of Leray, we give a precise definition of the notion of a cut Feynman integral in dimensional regularization, as a residue evaluated on the variety where some of the propagators are put on shell. These are naturally associated to Landau singularities of the first type. [...]
CERN-TH-2017-033; CP3-17-05; Edinburgh-2017-05; FR-PHENO-2017-001; arXiv:1702.03163.- 2017-06-14 - 56 p. - Published in : JHEP 1706 (2017) 114 Fulltext: PDF;

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2017-03-14
16:44
Thermodynamics of strongly-coupled lattice QCD in the chiral limit / de Forcrand, Philippe (Zurich, ETH ; CERN) ; Romatschke, Paul (Colorado U.) ; Unger, Wolfgang (Bielefeld U.) ; Vairinhos, Helvio (Zurich, ETH)
In the strong coupling limit, $n$-point functions in lattice QCD with staggered fermions can be rewritten exactly as sums over constrained configurations of monomers, dimers, and baryon loops covering the spacetime lattice. Worm algorithms provide efficient global sampling methods over such ensembles, and are particularly efficient in the chiral limit. [...]
arXiv:1701.08324; CERN-TH-2017-012.- 2017 - 7 p. - Published in : PoS: LATTICE2016 (2017) , pp. 086 Fulltext: PDF; Published version from PoS: PDF;
In : 34th International Symposium on Lattice Field Theory, Southampton, UK, 24 - 30 Jul 2016, pp.086

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