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Author |
Husek, T.; Monsalvez-Pozo, K.; Portoles, J. |
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Title |
Constraints on leptoquarks from lepton-flavour-violating tau-lepton processes |
Type |
Journal Article |
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Year |
2022 |
Publication  |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
165 - 31pp |
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Keywords |
Beyond Standard Model; Effective Field Theories |
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Abstract |
Leptoquarks are ubiquitous in several extensions of the Standard Model and seem to be able to accommodate the universality-violation-driven B-meson-decay anomalies and the (g-2)(mu) discrepancy interpreted as deviations from the Standard Model predictions. In addition, the search for lepton-flavour violation in the charged sector is, at present, a major research program that could also be facilitated by the dynamics generated by leptoquarks. In this article, we consider a rather wide framework of both scalar and vector leptoquarks as the generators of lepton-flavour violation in processes involving the tau lepton. We single out its couplings to leptoquarks, thus breaking universality in the lepton sector, and we integrate out leptoquarks at tree level, generating the corresponding dimension-6 operators of the Standard Model Effective Field Theory. In ref. [1] we obtained model-independent bounds on the Wilson coefficients of those operators contributing to lepton-flavour-violating hadron tau decays and l-tau conversion in nuclei, with l = e, mu. Hence, we use those results to translate the bounds into the couplings of leptoquarks to the Standard Model fermions. |
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Address |
[Husek, Tomas; Monsalvez-Pozo, Kevin; Portoles, Jorge] Univ Valencia, CSIC, Inst Fis Corpuscular, Apt Correus 2085, E-46071 Valencia, Spain, Email: tomas.husek@thep.lu.se; |
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Springer |
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English |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000788594400008 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5210 |
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Author |
Davier, M.; Diaz-Calderon, D.; Malaescu, B.; Pich, A.; Rodriguez-Sanchez, A.; Zhang, Z. |
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Title |
The Euclidean Adler function and its interplay with Delta alpha(had)(QED) and alpha(s) |
Type |
Journal Article |
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Year |
2023 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
067 - 57pp |
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Keywords |
Correlation Functions; Effective Field Theories of QCD; The Strong Coupling |
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Abstract |
Three different approaches to precisely describe the Adler function in the Euclidean regime at around 2 GeVs are available: dispersion relations based on the hadronic production data in e(+)e(-) annihilation, lattice simulations and perturbative QCD (pQCD). We make a comprehensive study of the perturbative approach, supplemented with the leading power corrections in the operator product expansion. All known contributions are included, with a careful assessment of uncertainties. The pQCD predictions are compared with the Adler functions extracted from ?a( QED)(had)(Q(2)), using both the DHMZ compilation of e(+)e(-) data and published lattice results. Taking as input the FLAG value of a(s), the pQCD Adler function turns out to be in good agreement with the lattice data, while the dispersive results lie systematically below them. Finally, we explore the sensitivity to a(s) of the direct comparison between the data-driven, lattice and QCD Euclidean Adler functions. The precision with which the renormalisation group equation can be tested is also evaluated. |
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Address |
[Davier, M.; Zhang, Z.] Univ Paris Saclay, CNRS IN2P3, IJCLab, F-91405 Orsay, France, Email: davier@lal.in2p3.fr; |
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Springer |
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English |
Summary Language |
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Series Editor |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:000985363600002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5533 |
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Author |
Penalva, N.; Flynn, J.M.; Hernandez, E.; Nieves, J. |
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Title |
Study of new physics effects in (B)over-bars → Ds(*) τ-(ν)over-bar τ semileptonic decays using lattice QCD form factors and heavy quark effective theory |
Type |
Journal Article |
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Year |
2024 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
163 - 33pp |
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Keywords |
Effective Field Theories of QCD; Flavour Symmetries; Semi-Leptonic Decays; SMEFT |
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Abstract |
We benefit from the lattice QCD determination by the HPQCD of the Standard Model (SM) form factors for the (B) over bar (s) -> D-s [Phys. Rev. D101(2020) 074513] and the SM and tensor ones for the (B) over bar (s) -> D-s* (arXiv:2304.03137[hep-lat]) semileptonic decays, and the heavy quark effective theory (HQET) relations for the analogous B -> D-(*()) decays obtained by F.U. Bernlochner et al. in Phys. Rev. D95(2017) 115008, to extract the leading and sub-leading Isgur-Wise functions for the (B) over bar (s) -> D-s(()*()) decays. Further use of the HQET relations allows us to evaluate the corresponding scalar, pseudoscalar and tensor form factors needed for a phenomenological study of new physics (NP) effects on the (B) over bar (s) -> D-s(()*()) semileptonic decay. At present, the experimental values for the ratios R-D(*) = Gamma[ (B) over bar -> D-(*())(tau- (nu) over bar tau)]/Gamma[(B) over bar -> D-(*())e(-)(mu(-)) (nu) over bar (e(mu))]are the best signal in favor of lepton flavor universality violation (LFUV) seen in charged current (CC) b -> c decays. In this work we conduct a study of NP effects on the (B) over bar (s) -> D-s(()*()) tau(-)(tau) semileptonic decays by comparing tau spin, angular and spin-angular asymmetry distributions obtained within the SM and three different NP scenarios. As expected from SU(3) light-flavor symmetry, we get results close to the ones found in a similar analysis of the (B) over bar -> D-(*()) case. The measurement of the (B) over bar (s) -> D-s(()*())(l (nu) over bar tau) semileptonic decays, which is within reach of present experiments, could then be of relevance in helping to establish or rule out LFUV in CC b -> c transitions. |
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Address |
[Penalva, Neus; Nieves, Juan] Ctr Mixto CSIC UV, Inst Fis Corpuscular, Inst Invest Paterna, C Catedrat Jose Beltran 2, E-46980 Paterna, Valencia, Spain, Email: neus.penalva@icc.ub.edu; |
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Publisher |
Springer |
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Editor |
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English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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Series Volume |
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ISSN |
1029-8479 |
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Expedition |
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Conference |
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Notes |
WOS:001152794800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5922 |
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Author |
Falkowski, A.; Gonzalez-Alonso, M.; Palavric, A.; Rodriguez-Sanchez, A. |
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Title |
Constraints on subleading interactions in beta decay Lagrangian |
Type |
Journal Article |
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Year |
2024 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
091 - 54pp |
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Keywords |
Effective Field Theories; Hadronic Matrix Elements and Weak Decays; Effective Field Theories of QCD; SMEFT |
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Abstract |
We discuss the effective field theory (EFT) for nuclear beta decay. The general quark-level EFT describing charged-current interactions between quarks and leptons is matched to the nucleon-level non-relativistic EFT at the OMeV momentum scale characteristic for beta transitions. The matching takes into account, for the first time, the effect of all possible beyond-the-Standard-Model interactions at the subleading order in the recoil momentum. We calculate the impact of all the Wilson coefficients of the leading and subleading EFT Lagrangian on the differential decay width in allowed beta transitions. As an example application, we show how the existing experimental data constrain the subleading Wilson coefficients corresponding to pseudoscalar, weak magnetism, and induced tensor interactions. The data display a 3.5 sigma evidence for nucleon weak magnetism, in agreement with the theory prediction based on isospin symmetry. |
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Address |
[Falkowski, Adam; Rodriguez-Sanchez, Antonio] Univ Paris Saclay, IJCLab, CNRS, IN2P3, F-91405 Orsay, France, Email: adam.falkowski@ijclab.in2p3.fr; |
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Springer |
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English |
Summary Language |
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Series Editor |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1029-8479 |
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Conference |
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Notes |
WOS:001163170700004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5966 |
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Author |
Boggia, M.; Cruz-Martinez, J.M.; Frellesvig, H.; Glover, N.; Gomez-Ambrosio, R.; Gonella, G.; Haddad, Y.; Ilnicka, A.; Jones, S.; Kassabov, Z.; Krauss, F.; Megy, T.; Melini, D.; Napoletano, D.; Passarino, G.; Patel, S.; Rodriguez-Vazquez, M.; Wolf, T. |
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Title |
The HiggsTools handbook: a beginners guide to decoding the Higgs sector |
Type |
Journal Article |
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Year |
2018 |
Publication |
Journal of Physics G |
Abbreviated Journal |
J. Phys. G |
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Volume |
45 |
Issue |
6 |
Pages |
065004 - 152pp |
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Keywords |
LHC physics; Higgs boson; new physics searches; effective field theories; Higgs momentum distributions |
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Abstract |
This report summarises some of the activities of the HiggsTools initial training network working group in the period 2015-2017. The main goal of this working group was to produce a document discussing various aspects of state-of-the-art Higgs physics at the large hadron collider (LHC) in a pedagogic manner The first part of the report is devoted to a description of phenomenological searches for new physics (NP) at the LHC. All of the available studies of the couplings of the new resonance discovered in 2012 by the ATLAS and CMS experiments (Aad et al (ATLAS Collaboration) 2012 Phys. Lett. B 716 1-29; Chatrchyan et al (CMS Collaboration) 2012 Phys. Lett. B 716 30-61) conclude that it is compatible with the Higgs boson of the standard model (SM) within present precision. So far the LHC experiments have given no direct evidence for any physical phenomena that cannot be described by the SM. As the experimental measurements become more and more precise, there is a pressing need for a consistent framework in which deviations from the SM predictions can be computed precisely. Such a framework should be applicable to measurements in all sectors of particle physics, not only LHC Higgs measurements but also electroweak precision data, etc. We critically review the use of the k-framework, fiducial and simplified template cross sections, effective field theories, pseudoobservables and phenomenological Lagrangians. Some of the concepts presented here are well known and were used already at the time of the large electron-positron collider (LEP) experiment. However, after years of theoretical and experimental development, these techniques have been refined, and we describe new tools that have been introduced in order to improve the comparison between theory and experimental data. In the second part of the report, we propose Phi(eta)* as a new and complementary observable for studying Higgs boson production at large transverse momentum in the case where the Higgs boson decays to two photons. The Phi(eta)* variable depends on measurements of the angular directions and rapidities of the two Higgs decay products rather than the energies, and exploits the information provided by the calorimeter in the detector. We show that, even without tracking information, the experimental resolution for Phi(eta)* is better than that of the transverse momentum of the photon pair, particularly at low transverse momentum. We make a detailed study of the phenomenology of the Phi(eta)* variable, contrasting the behaviour with the Higgs transverse momentum distribution using a variety of theoretical tools including event generators and fixed order perturbative computations. We consider the theoretical uncertainties associated with both p TH and Phi(eta)* distributions. Unlike the transverse momentum distribution, the Phi(eta)* distribution is well predicted using the Higgs effective field theory in which the top quark is integrated out-even at large values of Phi(eta)*-thereby making this a better observable for extracting the parameters of the Higgs interaction. In contrast, the potential of the Phi(eta)* distribution as a probe of NP is rather limited, since although the overall rate is affected by the presence of additional heavy fields, the shape of the Phi(eta)* distribution is relatively insensitive to heavy particle thresholds. |
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Address |
[Boggia, M.; Gonella, G.; Jones, S.; Megy, T.] Albert Ludwigs Univ Freiburg, Phys Inst, D-79104 Freiburg, Germany, Email: raquel.gomez-ambrosio@durham.ac.uk |
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Corporate Author |
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Thesis |
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Publisher |
Iop Publishing Ltd |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0954-3899 |
ISBN |
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Conference |
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Notes |
WOS:000434094000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3604 |
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