| 761. |
- Olsson, Jimmy, et al.
(författare)
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Resampling algorithms for high energy physics simulations
- 2020
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Ingår i: European Physical Journal C. - : Springer Science and Business Media Deutschland GmbH. - 1434-6044 .- 1434-6052. ; 80:10
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Tidskriftsartikel (refereegranskat)abstract
- We demonstrate that the method of interleaved resampling in the context of parton showers can tremendously improve the statistical convergence of weighted parton shower evolution algorithms. We illustrate this by several examples showing significant statistical improvement.
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| 762. |
- Ouyang, Hao, et al.
(författare)
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TT deformation of chiral bosons and Chern-Simons AdS3 gravity
- 2020
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Ingår i: European Physical Journal C. - : Springer Nature. - 1434-6044 .- 1434-6052. ; 80:12
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Tidskriftsartikel (refereegranskat)abstract
- We study the TT¯ deformation of the chiral bosons and show the equivalence between the chiral bosons of opposite chiralities and the scalar fields at the Hamiltonian level under the deformation. We also derive the deformed Lagrangian of more generic theories which contain an arbitrary number of chiral bosons to all orders. By using these results, we derive the TT¯ deformed boundary action of the AdS3 gravity theory in the Chern–Simons formulation. We compute the deformed one-loop torus partition function, which satisfies the TT¯ flow equation up to the one-loop order. Finally, we calculate the deformed stress–energy tensor of a solution describing a BTZ black hole in the boundary theory, which coincides with the boundary stress–energy tensor derived from the BTZ black hole with a finite cutoff.
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| 763. |
- Ozawa, K., et al.
(författare)
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Low mass dilepton production at RHIC energies.
- 2005
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 43, s. 421-426
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Tidskriftsartikel (refereegranskat)
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| 764. |
- Pagani, Davide, et al.
(författare)
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Improving NLO QCD event generators with high-energy EW corrections
- 2024
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Ingår i: European Physical Journal C. - : Springer. - 1434-6044 .- 1434-6052. ; 84:5
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present a new method for the combination of electroweak (EW) corrections at high energies, the so-called EW Sudakov logarithms (EWSL), and next-to-leading-order QCD predictions matched to parton-shower simulations (NLO+PS). Our approach is based on a reweighting procedure of NLO+PS events. In particular, both events with and without an extra hard emission from matrix elements are consistently reweighted via the inclusion of the corresponding EWSL contribution. We describe the technical details and the implementation in the MadGraph5_aMC@NLO framework. Via a completely automated procedure, events at this level of accuracy can be obtained for a vast class of hadroproduction processes. As a byproduct we provide results for phenomenologically relevant physical distributions from top-quark pair and Higgs boson associated production (t¯tH) and from the associated production of three Z gauge bosons (ZZZ).
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| 765. |
- Pasechnik, Roman, et al.
(författare)
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Drell-Yan diffraction: breakdown of QCD factorization
- 2011
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 71:12
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Tidskriftsartikel (refereegranskat)abstract
- We consider the diffractive Drell-Yan process in proton-(anti) proton collisions at high energies in the color dipole approach. The calculations are performed at forward rapidities of the leptonic pair. The effect of eikonalization of the universal "bare" dipole-target elastic amplitude in the saturation regime takes into account the principal part of the gap survival probability. We present predictions for the total and differential cross sections of the single-diffractive lepton-pair production at RHIC and LHC energies. We analyze implications of the QCD factorization breakdown in the diffractive Drell-Yan process, which is caused by a specific interplay of the soft and hard interactions, resulting in rather unusual properties of the corresponding observables.
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| 766. |
- Pasechnik, Roman, et al.
(författare)
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Vector-like technineutron Dark Matter: is a QCD-type Technicolor ruled out by XENON100?
- 2014
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; 74:2
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Tidskriftsartikel (refereegranskat)abstract
- One of the specific predictions of a new strongly coupled dynamics at a TeV scale is the existence of stable vector-like technibaryon states so that the lightest neutral one could serve as a Dark Matter candidate. We study the latter hypothesis in the QCD-type technicolor with SU (3)(TC) confined group and one SU (2)(W) doublet of vector-like techniquarks consistent with electroweak precision constraints and test it against the existing Dark Matter astrophysics data. We discuss the most stringent Dark Matter constraints on weak interactions of technibaryons in SU (3)(TC) technicolor and possible implications of these findings for the cosmological evolution of relic technineutrons. We conclude that vector-like techniquark sectors with an odd group of confinement SU(2n + 1)(TC), n = 1, 2, ... and with ordinary vector-like weak SU (2)(W) interactions are excluded by XENON100 data under the assumption of technibaryon number conservation in the modern Universe allowing for an even technicolor group SU (2n)(TC) only.
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| 767. |
- Pellen, Mathieu, et al.
(författare)
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Angular coefficients in W + j production at the LHC with high precision
- 2022
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 82:8
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Tidskriftsartikel (refereegranskat)abstract
- The extraction of the W-boson mass, a fundamental parameter of the Standard Model, from hadron-hadron collision requires precise theory predictions. In this regard, angular coefficients are crucial to model the dynamics of W-boson production. In this work, we provide, for the first time, angular coefficients at NNLO QCD + NLO EW accuracy for finite transverse momentum W-boson at the LHC. The corrections can reach up to 10 % in certain regions of phase space. They are accompanied by a significant reduction of the scale uncertainty. This work should, besides providing reference values for theory-data comparison, provide state-of-the-art theory input for W-boson mass measurements.
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| 768. |
- Prestel, Stefan, et al.
(författare)
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HYTREES : combining matrix elements and parton shower for hypothesis testing
- 2019
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 79:7
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Tidskriftsartikel (refereegranskat)abstract
- We present a new way of performing hypothesis tests on scattering data, by means of a perturbatively calculable classifier. This classifier exploits the “history tree” of how the measured data point might have evolved out of any simpler (reconstructed) points along classical paths, while explicitly keeping quantum–mechanical interference effects by copiously employing complete leading-order matrix elements. This approach extends the standard Matrix Element Method to an arbitrary number of final state objects and to exclusive final states where reconstructed objects can be collinear or soft. We have implemented this method into the standalone package hytrees and have applied it to Higgs boson production in association with two jets, with subsequent decay into photons. hytrees allows to construct an optimal classifier to discriminate this process from large Standard Model backgrounds. It further allows to find the most sensitive kinematic regions that contribute to the classification.
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| 769. |
- Prytz, Kjell
(författare)
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Signals of gluon recombination in deep inelastic scattering
- 2001
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Ingår i: European Physical Journal C. - : Springer Science and Business Media LLC. - 1434-6044 .- 1434-6052. ; 22:2, s. 317-321
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Tidskriftsartikel (refereegranskat)abstract
- The notion of a pomeron structure function arises in a model of electromagnetic diffractive scattering based on Regge factorization. Due to its small size we expect gluon recombination to occur significantly in the pomeron. The latest data from H1 (1999) show a Q(2) evolution in qualitative accordance with the GLR-MQ equations; these are the DGLAP (Altarelli-Parisi) equations corrected for the effect of gluon recombination.
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| 770. |
- Rasmussen, Christine O., et al.
(författare)
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Models for total, elastic and diffractive cross sections
- 2018
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Ingår i: European Physical Journal C. Particles and Fields. - : Springer Science and Business Media LLC. - 1434-6044. ; C78:6, s. 461-461
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Tidskriftsartikel (refereegranskat)
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