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Author |
Botella, F.J.; Branco, G.C.; Rebelo, M.N.; Silva-Marcos, J.I.; Bastos, J.F. |
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Title |
Decays of the heavy top and new insights on epsilon(K) in a one-VLQ minimal solution to the CKM unitarity problem |
Type |
Journal Article |
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Year |
2022 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
82 |
Issue |
4 |
Pages |
360 - 16pp |
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Keywords  |
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Abstract |
We propose a minimal extension of the Standard Model where an up-type vector-like quark, denoted T, is introduced and provides a simple solution to the CKM unitarity problem. We adopt the Botella-Chau parametrization in order to extract the 4 x 3 quark mixing matrix which contains the three angles of the 3 x 3 CKM matrix plus three new angles denoted theta(14), theta(24), theta(34). It is assumed that the mixing of T with standard quarks is dominated by theta(14). Imposing a recently derived, and much more restrictive, upper-bound on the New Physics contributions to epsilon(K) , we find, in the limit of exact theta(14) dominance where the other extra angles vanish, that epsilon(NP)(K) is too large. However, if one relaxes the exact theta(14) dominance limit, there exists a parameter region, where one may obtain epsilon(NP)(K) in agreement with experiment while maintaining the novel pattern of T decays with the heavy quark decaying predominantly to the light quarks d and u. We also find a reduction in the decay rate of K-L -> pi(0)nu(nu) over bar. |
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Address |
[Botella, Francisco J.] Univ Valencia, CSIC, Dept Fis Teor, Burjassot 46100, Spain, Email: Francisco.J.Botella@uv.es; |
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Springer |
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English |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6044 |
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Conference |
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Notes |
WOS:000787321000002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5206 |
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Author |
Sieber, H.; Banerjee, D.; Crivelli, P.; Depero, E.; Gninenko, S.N.; Kirpichnikov, D.V.; Kirsanov, M.M.; Poliakov, V.; Molina Bueno, L. |
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Title |
Prospects in the search for a new light Z0 boson with the NA64 μexperiment at the CERN SPS |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
105 |
Issue |
5 |
Pages |
052006 - 9pp |
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Keywords |
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Abstract |
A light Z0 vector boson coupled to the second and third lepton generations through the L μ- L tau current with mass below 200 MeV provides a very viable explanation in terms of new physics to the recently confirmed og – 2 thorn μanomaly. This boson can be produced in the bremsstrahlung reaction μN – μNZ0 after a high energy muon beam collides with a target. NA64 μis a fixed-target experiment using a 160 GeV muon beam from the CERN Super Proton Synchrotron accelerator looking for Z0 production and its subsequent decays, Z0 – invisible. In this paper, we present the study of the NA64 μsensitivity to search for such a boson. This includes a realistic beam simulation, a detailed description of the detectors and a discussion about the main potential background sources. A pilot run is scheduled in order to validate the simulation results. If those are confirmed, NA64 μwill be able to explore all the remaining parameter space which could provide an explanation for the g – 2 muon anomaly in the L μ- L tau model. |
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Address |
[Sieber, H.; Crivelli, P.; Depero, E.; Bueno, L. Molina] Swiss Fed Inst Technol, Inst Particle Phys & Astrophys, CH-8093 Zurich, Switzerland, Email: laura.molina.bueno@cern.ch |
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Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
2470-0010 |
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Expedition |
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Conference |
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Notes |
WOS:000787220100001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5207 |
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Author |
HAWC Collaboration (Albert, A. et al); Salesa Greus, F. |
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Title |
Long-term Spectra of the Blazars Mrk 421 and Mrk 501 at TeV Energies Seen by HAWC |
Type |
Journal Article |
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Year |
2022 |
Publication |
Astrophysical Journal |
Abbreviated Journal |
Astrophys. J. |
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Volume |
929 |
Issue |
2 |
Pages |
125 - 12pp |
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Keywords |
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Abstract |
The High Altitude Water Cherenkov (HAWC) Gamma-Ray Observatory surveys the very high-energy sky in the 300 GeV to >100 TeV energy range. HAWC has detected two blazars above 11 sigma, Markarian 421 (Mrk 421) and Markarian 501 (Mrk 501). The observations are comprised of data taken in the period between 2015 June and 2018 July, resulting in similar to 1038 days of exposure. In this work, we report the time-averaged spectral analyses for both sources, above 0.5 TeV. Taking into account the flux attenuation due to the extragalactic background light, the intrinsic spectrum of Mrk 421 is described by a power law with an exponential energy cutoff with index alpha = 2.26 +/- (0.12)(stat)((+0.17)(-0.2))(sys) and energy cutoff E-c = 5.1 +/- (1.6)(stat)((+1.4)(-2.5))(sys) TeV, while the intrinsic spectrum of Mrk 501 is better described by a simple power law with index alpha = 2.61 +/- (0.11)(stat)((+)(0.01)(-0.07))(sys). The maximum energies at which the Mrk 421 and Mrk 501 signals are detected are 9 and 12 TeV, respectively. This makes these some of the highest energy detections to date for spectra averaged over years-long timescales. Since the observation of gamma radiation from blazars provides information about the physical processes that take place in their relativistic jets, it is important to study the broadband spectral energy distributions (SEDs) of these objects. For this purpose, contemporaneous data in the gamma-ray band to the X-ray range, and literature data in the radio to UV range, were used to build time-averaged SEDs that were modeled within a synchrotron-self Compton leptonic scenario. |
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Address |
[Albert, A.; Durocher, M.; Harding, J. P.] Los Alamos Natl Lab, Phys Div, Los Alamos, NM 87545 USA, Email: alberto@inaoep.mx; |
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Corporate Author |
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Publisher |
IOP Publishing Ltd |
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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 |
0004-637x |
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Notes |
WOS:000785694100001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5209 |
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Author |
Guevara, A.; Lopez Castro, G.; Roig, P. |
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Title |
Improved description of dilepton production in tau(-) -> nu(tau)P(- )decays |
Type |
Journal Article |
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Year |
2022 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
105 |
Issue |
7 |
Pages |
076007 - 15pp |
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Keywords |
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Abstract |
Recently, the Belle Collaboration reported the first measurements of the tau(-) -> nu(tau)pi(-) e(+) e(-) branching fraction and the spectrum of the pion-dielectron system. In an analysis previous to Belle's results, we evaluated this branching fraction which turned out to be compatible with that reported by Belle, although with a large uncertainty. This is the motivation to seek for improvement on our previous evaluation of tau(-) -> nu(tau)pi(-) l(+) l(-) decays (l = e, mu). In this paper we improve our calculation of the WP-gamma* vertex by including flavor-symmetry breaking effects in the framework of the resonance chiral theory. We impose QCD short-distance behavior to constrain most parameters and data on the pi(-) e(+) e(-) spectrum reported by the Belle Collaboration to fix the remaining free ones. As a result, improved predictions for the branching ratios and hadronic/leptonic spectra are reported, which are in good agreement with observations. Analogous calculations for the strangeness-changing tau(-) -> nu(tau) K- l(+) l(-) transitions are reported for the first time. Albeit one expects the m(pi mu+ mu- )spectrum to be measured in Belle-II and the observables with l = e can be improved, it is rather unlikely that the K channels can be measured due to the suppression factor vertical bar V-ud/V-us vertical bar(2) = 0.05. |
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Address |
[Guevara, Adolfo] Univ Granada, Dept Fis Atom Mol & Nucl, E-18071 Granada, Spain |
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Corporate Author |
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Publisher |
Amer Physical Soc |
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 |
2470-0010 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000789304200003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5212 |
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Author |
LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. |
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Title |
Search for massive long-lived particles decaying semileptonically at root s=13 TeV |
Type |
Journal Article |
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Year |
2022 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
82 |
Issue |
4 |
Pages |
373 - 19pp |
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Keywords |
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Abstract |
A search is performed for massive long-lived particles (LLPs) decaying semileptonically into a muon and two quarks. Two kinds of LLP production processes were considered. In the first, a Higgs-like boson with mass from 30 to 200 GeV/c(2) is produced by gluon fusion and decays into two LLPs. The analysis covers LLP mass values from 10 GeV/c(2) up to about one half the Higgs-like boson mass. The second LLP production mode is directly from quark interactions, with LLP masses from 10 to 90 GeV/c(2). The LLP lifetimes considered range from 5 to 200 ps. This study uses LHCb data collected from proton-proton collisions at root s = 13 TeV, corresponding to an integrated luminosity of 5.4 fb(-1). No evidence of these long-lived states has been observed, and upper limits on the production cross-section times branching ratio have been set for each model considered. |
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Address |
[LHCb Collaboration] CERN, CH-1211 Geneva 23, Switzerland, Email: aurelio.bay@epfl.ch |
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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 |
1434-6044 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000788631800002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5213 |
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