| Records |
| Author |
Campanario, F.; Rauch, M.; Sapeta, S. |
Title  |
W+W- production at high transverse momenta beyond NLO |
Type |
Journal Article |
| Year |
2014 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
| Volume |
879 |
Issue |
|
Pages |
65-79 |
| Keywords |
|
| Abstract |
Pair production of W gauge bosons is an important process at the LHC entering many experimental analyses, both as background in new-physics searches or Higgs measurements and as signal in precision studies and tests of the Standard Model. Therefore, accurate predictions for this class of processes are of great interest in order to exploit the full potential of LHC measurements. We use the LoopSim method to combine NLO QCD results for WW and WW + jet, as well as the loop-squared gluon-fusion contribution, to obtain approximate NNLO predictions for WW production. The cross sections are calculated with VBFNLO and include leptonic decays of the W bosons as well as finite-width and off-shell effects. We find that the size of the additional corrections beyond NLO can be significant and well outside of the NLO error bands given by renormalization and factorization scale variation. Applying a jet veto, we observe further negative corrections at NNLO. which we relate to the presence of large Sudakov logarithms. |
| Address |
[Campanario, Francisco] Univ Valencia, CSIC, IFIC, Div Theory, E-46980 Valencia, Spain, Email: francisco.campanario@ific.uv.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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 |
|
Edition |
|
| ISSN |
0550-3213 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000332352600004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
1734 |
| Permanent link to this record |
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| Author |
Aguilar-Saavedra, J.A.; Bernabeu, J. |
| Title |
W polarisation beyond helicity fractions in top quark decays |
Type |
Journal Article |
| Year |
2010 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
| Volume |
840 |
Issue |
1-2 |
Pages |
349-378 |
| Keywords |
|
| Abstract |
We calculate the density matrix for the decay of a polarised top quark into a polarised W boson and a massive 17 quark, for the most general Wth vertex arising from dimension-six gauge-invariant effective operators. We show that, in addition to the well-known W helicity fractions, for polarised top decays it is worth defining and studying the transverse and normal W polarisation fractions, that is, the W polarisation alone two directions orthogonal to its momentum. In particular, a rather simple forward-backward asymmetry in the normal direction is found to be very sensitive to complex phases in one of the Wth anomalous couplings. This asymmetry, which indicates a normal W polarisation, can be generated for example by a P-odd. T-odd transition electric dipole moment. We also investigate the angular distribution of decay products in the top quark rest frame, calculating the spin analysing powers for a general Wth vertex. Finally we show that, using a combined fit to top decay observables and the t W cross section, at LHC it will be possible to obtain model-independent measurements of all the (complex) Wth couplings as well as the single top polarisation. Implications for spin correlations in top pair production are also discussed. |
| Address |
[Aguilar-Saavedra, J. A.] Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain, Email: jaas@ugr.es |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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 |
0550-3213 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000281832900013 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
370 |
| Permanent link to this record |
| |
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| |
| Author |
Penalva, N.; Hernandez, E.; Nieves, J. |
| Title |
Visible energy and angular distributions of the charged particle from the tau-decay in b -> C tau (mu(nu)over-bar(mu)nu(tau), pi nu(tau), rho nu(tau))(nu)over-bar(tau) reactions |
Type |
Journal Article |
| Year |
2022 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
04 |
Issue |
4 |
Pages |
026 - 25pp |
| Keywords |
Bottom Quarks; Semi-Leptonic Decays; Flavour Symmetries; Left-Right Models |
| Abstract |
We study the d(2)Gamma(d)/(d omega d cos theta(d) ), d Gamma(d)/d cos theta(d) and d Gamma(d)/dE(d) distributions, which are defined in terms of the visible energy and polar angle of the charged particle from the tau-decay in b -> C tau (mu(nu) over bar (mu)nu(tau), pi nu(tau), rho nu(tau))(nu) over bar (tau), reactions. These differential decay widths could be measured in the near future with certain precision. The first two contain information on the transverse tau-spin, tau-angular and tau-angular-spin asymmetries of the H-b -> H-c tau(nu) over bar (tau) parent decay and, from a dynamical point of view, they are richer than the commonly used one, d(2)Gamma(d)/(d omega dE(d)), since the latter only depends on the tau longitudinal polarization. We pay attention to the deviations with respect to the predictions of the standard model (SM) for these new observables, considering new physics (NP) operators constructed using both right- and left-handed neutrino fields, within an effective field-theory approach. We present results for Lambda(b) -> Lambda(c)tau (mu(nu) over bar (mu)nu(tau), pi nu(tau), rho nu(tau))(nu) over bar (tau) and (B) over bar -> D-(*()) tau (mu(nu) over bar (mu)nu(tau), pi nu(tau), rho nu(tau))(nu) over bar (tau) sequential decays and discuss their use to disentangle between different NP models. In this respect, we show that d Gamma(d)/d cos theta(d) , which should be measured with sufficiently good statistics, becomes quite useful, especially in the tau -> pi nu(tau) mode. The study carried out in this work could be of special relevance due to the recent LHCb measurement of the lepton flavor universality ratio R Lambda(c) in agreement with the SM. The experiment identified the tau using its hadron decay into pi(-)pi(+)pi(-)nu(tau), and this result for R Lambda(c )which is in conflict with the phenomenology from the b-meson sector, needs confirmation from other tau reconstruction channels. |
| Address |
[Penalva, Neus; Nieves, Juan] Inst Fis Corpuscular Ctr Mixto CSIC UV, Inst Invest Paterna, C Catedrat Jose Beltran 2, E-46980 Valencia, Spain, Email: neuspe@ific.uv.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Springer |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
|
| Series Editor |
|
Series Title |
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Abbreviated Series Title |
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| Series Volume |
|
Series Issue |
|
Edition |
|
| ISSN |
1029-8479 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000781361300001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
5195 |
| Permanent link to this record |
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| |
| Author |
Pich, A.; Rodriguez-Sanchez, A. |
| Title |
Violations of quark-hadron duality in low-energy determinations of alpha(s) |
Type |
Journal Article |
| Year |
2022 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
07 |
Issue |
7 |
Pages |
145 - 42pp |
| Keywords |
The Strong Coupling; Semi-Leptonic Decays; Specific QCD Phenomenology; Chiral Lagrangian |
| Abstract |
Using the spectral functions measured in tau decays, we investigate the actual numerical impact of duality violations on the extraction of the strong coupling. These effects are tiny in the standard alpha(s)(m(tau)(2)) determinations from integrated distributions of the hadronic spectrum with pinched weights, or from the total tau hadronic width. The pinched-weight factors suppress very efficiently the violations of duality, making their numerical effects negligible in comparison with the larger perturbative uncertainties. However, combined fits of alpha(s) and duality-violation parameters, performed with non-protected weights, are subject to large systematic errors associated with the assumed modelling of duality-violation effects. These uncertainties have not been taken into account in the published analyses, based on specific models of quark-hadron duality. |
| Address |
[Pich, Antonio] Univ Valencia, Dept Fis Teor, CSIC, IFIC, Parque Cient,Catedrat Jose Beltran 2, E-46980 Paterna, Spain, Email: Antonio.Pich@ific.uv.es; |
| Corporate Author |
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Thesis |
|
| Publisher |
Springer |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
|
| Series Editor |
|
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 |
1029-8479 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000831256400009 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5303 |
| Permanent link to this record |
| |
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| |
| Author |
Lopez-Honorez, L.; Mena, O.; Palomares-Ruiz, S.; Villanueva-Domingo, P.; Witte, S.J. |
| Title |
Variations in fundamental constants at the cosmic dawn |
Type |
Journal Article |
| Year |
2020 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
| Volume |
06 |
Issue |
6 |
Pages |
026 - 25pp |
| Keywords |
cosmology of theories beyond the SM; particle physics – cosmology connection; reionization |
| Abstract |
The observation of space-time variations in fundamental constants would provide strong evidence for the existence of new light degrees of freedom in the theory of Nature. Robustly constraining such scenarios requires exploiting observations that span different scales and probe the state of the Universe at different epochs. In the context of cosmology, both the cosmic microwave background and the Lyman-a forest have proven to be powerful tools capable of constraining variations in electromagnetism, however at the moment there do not exist cosmological probes capable of bridging the gap between recombination and reionization. In the near future, radio telescopes will attempt to measure the 21 cm transition of neutral hydrogen during the epochs of reionization and the cosmic dawn (and potentially the tail end of the dark ages); being inherently sensitive to electromagnetic phenomena, these experiments will offer a unique perspective on space-time variations of the fine-structure constant and the electron mass. We show here that large variations in these fundamental constants would produce features on the 21 cm power spectrum that may be distinguishable from astrophysical uncertainties. Furthermore, we forecast the sensitivity for the Square Kilometer Array, and show that the 21 cm power spectrum may be able to constrain variations at the level of O(10(-3)). |
| Address |
[Lopez-Honorez, Laura] Univ Libre Bruxelles, Serv Phys Theor, CP225, B-1050 Brussels, Belgium, Email: llopezho@ulb.ac.be; |
| 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 |
|
Series Issue |
|
Edition |
|
| ISSN |
1475-7516 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000551875400049 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4473 |
| Permanent link to this record |
| |
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| |
| Author |
HAWC Collaboration (Alfaro, R. et al); Salesa Greus, F. |
| Title |
Validation of standardized data formats and tools for ground-level particle-based gamma-ray observatories |
Type |
Journal Article |
| Year |
2022 |
Publication |
Astronomy & Astrophysics |
Abbreviated Journal |
Astron. Astrophys. |
| Volume |
667 |
Issue |
|
Pages |
A36 - 12pp |
| Keywords |
methods; data analysis; gamma rays; general |
| Abstract |
Context. Ground-based gamma-ray astronomy is still a rather young field of research, with strong historical connections to particle physics. This is why most observations are conducted by experiments with proprietary data and analysis software, as is usual in the particle physics field. However, in recent years, this paradigm has been slowly shifting toward the development and use of open-source data formats and tools, driven by upcoming observatories such as the Cherenkov Telescope Array (CTA). In this context, a community-driven, shared data format (the gamma-astro-data-format, or GADF) and analysis tools such as Gammapy and ctools have been developed. So far, these efforts have been led by the Imaging Atmospheric Cherenkov Telescope community, leaving out other types of ground-based gamma-ray instruments. Aims. We aim to show that the data from ground particle arrays, such as the High-Altitude Water Cherenkov (HAWC) observatory, are also compatible with the GADF and can thus be fully analyzed using the related tools, in this case, Gammapy. Methods. We reproduced several published HAWC results using Gammapy and data products compliant with GADF standard. We also illustrate the capabilities of the shared format and tools by producing a joint fit of the Crab spectrum including data from six different gamma-ray experiments. Results. We find excellent agreement with the reference results, a powerful confirmation of both the published results and the tools involved. Conclusions. The data from particle detector arrays such as the HAWC observatory can be adapted to the GADF and thus analyzed with Gammapy. A common data format and shared analysis tools allow multi-instrument joint analysis and effective data sharing. To emphasize this, a sample of Crab nebula event lists is made public with this paper. Because of the complementary nature of pointing and wide-field instruments, this synergy will be distinctly beneficial for the joint scientific exploitation of future observatories such as the Southern Wide-field Gamma-ray Observatory and CTA. |
| Address |
[Albert, A.; Durocher, M.; Harding, J. P.] Los Alamos Natl Lab, Phys Div, Los Alamos, NM USA, Email: laura.olivera-nieto@mpi-hd.mpg.de |
| Corporate Author |
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Thesis |
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| Publisher |
Edp Sciences S A |
Place of Publication |
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Editor |
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| Language |
English |
Summary Language |
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Original Title |
|
| 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 |
0004-6361 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000879223700008 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
5408 |
| Permanent link to this record |
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| Author |
Battye, R.A.; Brawn, G.D.; Pilaftsis, A. |
| Title |
Vacuum topology of the two Higgs doublet model |
Type |
Journal Article |
| Year |
2011 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
08 |
Issue |
8 |
Pages |
020 - 75pp |
| Keywords |
Higgs Physics; Spontaneous Symmetry Breaking; CP violation |
| Abstract |
We perform a systematic study of generic accidental Higgs-family and CP symmetries that could occur in the two-Higgs-doublet-model potential, based on a Majorana scalar-field formalism which realizes a subgroup of GL(8, C). We derive the general conditions of convexity and stability of the scalar potential and present analytical solutions for two non-zero neutral vacuum expectation values of the Higgs doublets for a typical set of six symmetries, in terms of the gauge-invariant parameters of the theory. By means of a homotopy-group analysis, we identify the topological defects associated with the spontaneous symmetry breaking of each symmetry, as well as the massless Goldstone bosons emerging from the breaking of the continuous symmetries. We find the existence of domain walls from the breaking of Z(2), CP1 and CP2 discrete symmetries, vortices in models with broken U(1)(PQ) and CP3 symmetries and a global monopole in the SO(3)(HF)-broken model. The spatial profile of the topological defect solutions is studied in detail, as functions of the potential parameters of the two-Higgs doublet model. The application of our Majorana scalar-field formalism in studying more general scalar potentials that are not constrained by the U(1)(Y) hypercharge symmetry is discussed. In particular, the same formalism may be used to properly identify seven additional symmetries that may take place in a U(1)(Y)-invariant scalar potential. |
| Address |
[Battye, RA; Brawn, GD] Univ Manchester, Jodrell Bank, Ctr Astrophys, Sch Phys & Astron, Manchester M13 9PL, Lancs, England, Email: rbattye@jb.man.ac.uk |
| Corporate Author |
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Thesis |
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| Publisher |
Springer |
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 |
1126-6708 |
ISBN |
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Medium |
|
| Area |
|
Expedition |
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Conference |
|
| Notes |
WOS:000294901400062 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
765 |
| Permanent link to this record |
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| Author |
Bonilla, C.; Fonseca, R.M.; Valle, J.W.F. |
| Title |
Vacuum stability with spontaneous violation of lepton number |
Type |
Journal Article |
| Year |
2016 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
756 |
Issue |
|
Pages |
345-349 |
| Keywords |
|
| Abstract |
The vacuum of the Standard Model is known to be unstable for the measured values of the top and Higgs masses. Here we show how vacuum stability can be achieved naturally if lepton number is violated spontaneously at the TeV scale. More precise Higgs measurements in the next LHC run should provide a crucial test of our symmetry breaking scenario. In addition, these schemes typically lead to enhanced rates for processes involving lepton flavor violation. |
| Address |
[Bonilla, Cesar; Fonseca, Renato M.; Valle, Jose W. F.] Univ Valencia, AHEP Grp, Inst Fis Corpuscular, CSIC, Parc Cient Paterna,C Catedrat Jose Beltran 2, E-46980 Valencia, Spain, Email: cesar.bonilla@ific.uv.es; |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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 |
0370-2693 |
ISBN |
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Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
WOS:000373569200053 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
2638 |
| Permanent link to this record |
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| Author |
Yamagata-Sekihara, J.; Oset, E. |
| Title |
V P gamma radiative decay of resonances dynamically generated from the vector meson-vector meson interaction |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
| Volume |
690 |
Issue |
4 |
Pages |
376-381 |
| Keywords |
Local hidden gauge; Radiative decays; Vector mesons; Dynamically generated resonances |
| Abstract |
We evaluate the radiative decay into a vector, a pseudoscalar and a photon of several resonances dynamically generated from the vector-vector interaction. The process proceeds via the decay of one of the vector components into a pseudoscalar and a photon, which have an invariant mass distribution very different from phase space as a consequence of the two vector structure of the resonances. Experimental work along these lines should provide useful information on the nature of these resonances. |
| Address |
[Yamagata-Sekihara, J.] Univ Valencia, Ctr Mixto, CSIC, Inst Invest Paterna,Dept Fis Teor, Valencia 46071, Spain, Email: yamagata@ific.uv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Elsevier Science Bv |
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 |
0370-2693 |
ISBN |
|
Medium |
|
| Area |
|
Expedition |
|
Conference |
|
| Notes |
ISI:000279835300008 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ elepoucu @ |
Serial |
408 |
| Permanent link to this record |
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| Author |
Khosa, C.K.; Sanz, V.; Soughton, M. |
| Title |
Using machine learning to disentangle LHC signatures of Dark Matter candidates |
Type |
Journal Article |
| Year |
2021 |
Publication |
Scipost Physics |
Abbreviated Journal |
SciPost Phys. |
| Volume |
10 |
Issue |
6 |
Pages |
151 - 26pp |
| Keywords |
|
| Abstract |
We study the prospects of characterising Dark Matter at colliders using Machine Learning (ML) techniques. We focus on the monojet and missing transverse energy (MET) channel and propose a set of benchmark models for the study: a typical WIMP Dark Matter candidate in the form of a SUSY neutralino, a pseudo-Goldstone impostor in the shape of an Axion-Like Particle, and a light Dark Matter impostor whose interactions are mediated by a heavy particle. All these benchmarks are tensioned against each other, and against the main SM background (Z+jets). Our analysis uses both the leading-order kinematic features as well as the information of an additional hard jet. We explore different representations of the data, from a simple event data sample with values of kinematic variables fed into a Logistic Regression algorithm or a Fully Connected Neural Network, to a transformation of the data into images related to probability distributions, fed to Deep and Convolutional Neural Networks. We also study the robustness of our method against including detector effects, dropping kinematic variables, or changing the number of events per image. In the case of signals with more combinatorial possibilities (events with more than one hard jet), the most crucial data features are selected by performing a Principal Component Analysis. We compare the performance of all these methods, and find that using the 2D images of the combined information of multiple events significantly improves the discrimination performance. |
| Address |
[Khosa, Charanjit Kaur; Sanz, Veronica; Soughton, Michael] Univ Sussex, Dept Phys & Astron, Brighton BN1 9QH, E Sussex, England, Email: Charanjit.Kaur@sussex.ac.uk; |
| Corporate Author |
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Thesis |
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| Publisher |
Scipost Foundation |
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 |
2542-4653 |
ISBN |
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Medium |
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| Area |
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Expedition |
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Conference |
|
| Notes |
WOS:000680038800002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
4927 |
| Permanent link to this record |
