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Author  |
Li, X.Q.; Yang, Y.D.; Yuan, X.B. |
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Title |
Anomalous tqZ coupling effects in rare B- and K-meson decays |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
03 |
Issue |
3 |
Pages |
018 - 22pp |
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Keywords |
Rare Decays; Beyond Standard Model; B-Physics; Kaon Physics |
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Abstract |
As a top-factory, the LHC is performing a direct study of top-quark anomalous FCNC couplings, which are, however, correlated closely with the rare B- and K-meson decays. In this paper, we study the effects of anomalous tqZ (with q = u, c) couplings in the rare decays B-s,B-d -> mu(+)mu(-), B -> X-s nu(nu) over bar, B -> K(*)nu(nu) over bar, K+ -> pi(+)nu(nu) over bar, and K-L -> pi(0)nu(nu) over bar. With the up-to-date experimental bounds on the branching ratios of these channels, constraints on the left-handed anomalous couplings X-ct(L), and X-ut(L) are derived, respectively. With these low-energy constraints taken into account, we find that, for real couplings X-ct(L) and X-ut(L), the indirect upper bounds on B(t -> qZ) are much lower than that from the D0 collaboration, but are still compatible with the 5 sigma discovery potential of ATLAS with an integrated luminosity of 10 fb(-1). With refined measurements to be available at the LHCb, the future super-B factories, the NA62 at CERN, and the KOTO at J-PARC, closer correlations between the t -> qZ and the rare B- and K-meson decays are expected in the near future, which will be helpful for the searches of thu e top-quark FCNC decays at the LHC. |
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Address |
[Li, Xin-Qiang] Henan Normal Univ, Dept Phys, Xinxiang 453007, Henan, Peoples R China, Email: xqli@itp.ac.cn; |
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Springer |
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English |
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ISSN |
1126-6708 |
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Expedition |
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Conference |
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Notes |
WOS:000302412100018 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1011 |
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Author |
Li, X.Q.; Li, Y.M.; Lu, G.R.; Su, F. |
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Title |
B-s(0)-(B)over-bar(s)(0) mixing in a family non-universal Z ' model revisited |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
05 |
Issue |
5 |
Pages |
049 - 27pp |
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Keywords |
Beyond Standard Model; B-Physics; CP violation |
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Abstract |
Motivated by the very recent measurements performed at the LHCb and the Tevatron of the B-s(0) – (B) over bar (0)(s) mixing, in this paper we revisit it in a family non-universal Z' model, to check if a simultaneous explanation for all the mixing observables, especially for the like-sign dimuon charge asymmetry observed by the D0 collaboration, could be made in such a specific model. In the first scenario where the Z' boson contributes only to the off-diagonal element M-12(s), it is found that, once the combined constraints from Delta M-s, phi(s) and Delta Gamma(s) are imposed, the model could not explain the measured flavour-specific CP asymmetry a(fs)(s), at least within its 1 sigma ranges. In the second scenario where the NP contributes also to the absorptive part Gamma(s)(12) via tree-level Z'-induced b -> c (c) over bars operators, we find that, with the constraints from Delta M-s, phi(s) and the indirect CP asymmetry in (B) over bar (d) -> J/psi K-S taken into account, the present measured 1 sigma experimental ranges for a(fs)(s) could not be reproduced too. Thus, such a specific Z' model with our specific assumptions could not simultaneously reconcile all the present data on B-s(0) – B-s(0) mixing. Future improved measurements from the LHCb and the proposed superB experiments, especially of the flavour-specific CP asymmetries, are expected to shed light on the issue. |
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Address |
[Li, Xin-Qiang; Li, Yan-Min; Lu, Gong-Ru] Henan Normal Univ, Dept Phys, Xinxiang 453007, Henan, Peoples R China, Email: xqli@itp.ac.cn; |
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Springer |
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ISSN |
1126-6708 |
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Expedition |
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Conference |
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Notes |
WOS:000305236000049 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1103 |
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Author |
Lesgourgues, J.; Pastor, S. |
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Title |
Neutrino Mass from Cosmology |
Type |
Journal Article |
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Year |
2012 |
Publication |
Advances in High Energy Physics |
Abbreviated Journal |
Adv. High. Energy Phys. |
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Volume |
2012 |
Issue |
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Pages |
608515 - 34pp |
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Keywords |
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Abstract |
Neutrinos can play an important role in the evolution of the universe, modifying some of the cosmological observables. In this contribution we summarize the main aspects of cosmological relic neutrinos, and we describe how the precision of present cosmological data can be used to learn about neutrino properties, in particular their mass, providing complementary information to beta decay and neutrinoless double-beta decay experiments. We show how the analysis of current cosmological observations, such as the anisotropies of the cosmic microwave background or the distribution of large-scale structure, provides an upper bound on the sum of neutrino masses of order 1 eV or less, with very good perspectives from future cosmological measurements which are expected to be sensitive to neutrino masses well into the sub-eV range. |
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Address |
[Pastor, Sergio] Univ Valencia, CSIC, Inst Fis Corpuscular, Valencia 46071, Spain, Email: pastor@ific.uv.es |
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Publisher |
Hindawi Publishing Corporation |
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Language |
English |
Summary Language |
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Original Title |
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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 |
1687-7357 |
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Conference |
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Notes |
WOS:000312317500001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1278 |
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Author |
Lee, J.S.; Pilaftsis, A. |
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Title |
Radiative corrections to scalar masses and mixing in a scale invariant two Higgs doublet model |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
86 |
Issue |
3 |
Pages |
035004 - 14pp |
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Keywords |
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Abstract |
We study the Higgs boson mass spectrum of a classical scale invariant realization of the two Higgs doublet model (SI-2HDM). The classical scale symmetry of the theory is explicitly broken by quantum loop effects due to gauge interactions, Higgs self-couplings and top quark Yukawa couplings. We determine the allowed parameter space compatible with perturbative unitarity and electroweak precision data. Taking into account the LEP and the recent LHC exclusion limits on a standard-model-like Higgs boson HSM, we obtain rather strict constraints on the mass spectrum of the heavy Higgs sector of the SI-2HDM. In particular, if MHSM 125 GeV, the SI-2HDM strongly favors scenarios in which at least one of the nonstandard neutral Higgs bosons has a mass close to 400 GeV and is generically degenerate with the charged Higgs boson, whilst the third neutral Higgs scalar is lighter than 500 GeV. |
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Address |
[Lee, Jae Sik] Natl Tsing Hua Univ, Dept Phys, Hsinchu 300, Taiwan |
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Publisher |
Amer Physical Soc |
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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 |
1550-7998 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000307122700007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1113 |
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Author |
Ledwig, T.; Martin-Camalich, J.; Pascalutsa, V.; Vanderhaeghen, M. |
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Title |
Nucleon and Delta(1232) form factors at low momentum transfer and small pion masses |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
85 |
Issue |
3 |
Pages |
034013 - 25pp |
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Keywords |
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Abstract |
An expansion of the electromagnetic form factors of the nucleon and Delta(1232) in small momentum transfer and pion mass is performed in a manifestly covariant EFT framework consistent with chiral symmetry and analyticity. We present the expressions for the nucleon and Delta(1232) electromagnetic form factors, charge radii, and electromagnetic moments in the framework of SU(2) baryon chiral perturbation theory, with nucleon and Delta-isobar degrees of freedom, to next-to-leading order. Motivated by the results for the proton electric radius obtained from the muonic-hydrogen atom and electron-scattering process, we extract values for the second derivative of the electric form factor which is a genuine prediction of the p(3) B chi PT. The chiral behavior of radii and moments is studied and compared to that obtained in the heavy-baryon framework and lattice QCD. The chiral behavior of Delta(1232)-isobar properties exhibits cusps and singularities at the threshold of Delta -> pi N decay, and their physical significance is discussed. |
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Address |
[Ledwig, T.; Pascalutsa, V.; Vanderhaeghen, M.] Johannes Gutenberg Univ Mainz, Inst Kernphys, D-55099 Mainz, Germany, Email: ledwig@kph.uni-mainz.de |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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 |
1550-7998 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300093200003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
894 |
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| Permanent link to this record |
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Author |
Kuhn, J.H.; Rodrigo, G. |
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Title |
Charge asymmetries of top quarks at hadron colliders revisited |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
063 - 25pp |
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Keywords |
Heavy Quark Physics; Hadronic Colliders; Standard Model; Beyond Standard Model |
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Abstract |
A sizeable difference in the differential production cross section of top-compared to antitop-quark production, denoted charge asymittetm has been observed at the Tevatron. The experimental results seem to exceed the theory predictions based on the Standard Model by a significant amount and have triggered a large number of suggestions for “new physics'. In the present paper the Standard Model predictions for Tevatron and LHe experiments are revisited. This includes a reanalysis of electromagnetic as well as weak corrections, leading to a shift of the asymmetry by roughly a factor 1.1 when compared to the results of the first papers on this subject. The impact of cuts on the transverse momentum of the top-antitop system is studied. Restricting the it system to a transverse momentum less than 20 GeV leads to an enhancement of the asymmetries by factors between 1.3 and 1.5, indicating the importance of an improved understanding of the tt-momentum distribution. Predictions for similar measurements at the LHC are presented, demonstrating the sensitivity of the large rapidity region bot ti to the Standard Model contribution and effects from ”new physics". |
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Address |
[Kuehn, Johann H.] Karlsruher Inst Technol, Inst Theoret Teilchenphys, D-76133 Karlsruhe, Germany, Email: johann.kuehn@kit.edu |
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Publisher |
Springer |
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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 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300181800063 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
971 |
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Author |
Kowalska, M.; Naimi, S.; Agramunt, J.; Algora, A.; Beck, D.; Blank, B.; Blaum, K.; Bohm, C.; Borgmann, C.; Breitenfeldt, M.; Fraile, L.M.; George, S.; Herfurth, F.; Herlert, A.; Kreim, S.; Lunney, D.; Minaya-Ramirez, E.; Neidherr, D.; Rosenbusch, M.; Rubio, B.; Schweikhard, L.; Stanja, J.; Zuber, K. |
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Title |
Trap-assisted decay spectroscopy with ISOLTRAP |
Type |
Journal Article |
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Year |
2012 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
689 |
Issue |
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Pages |
102-107 |
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Keywords |
Penning trap mass spectrometers; Trap-assisted decay spectroscopy; Studies at ISOL-type facilities |
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Abstract |
Penning traps are excellent high-precision mass spectrometers for radionuclides. The high-resolving power used for cleaning isobaric and even isomeric contaminants can be exploited to improve decay-spectroscopy studies by delivering purified samples. An apparatus allowing trap-assisted decay spectroscopy has been coupled to the ISOLTRAP mass spectrometer at ISOLDE/CERN. The results from studies with stable and radioactive ions show that the setup can be used to perform decay studies on purified short-lived nuclides and to assist mass measurements. |
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Address |
[Kowalska, M.; Herlert, A.] CERN, Dept Phys, CH-1211 Geneva 23, Switzerland, Email: kowalska@cern.ch |
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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 |
0168-9002 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000307797500016 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1134 |
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Author |
Kleiss, R.H.P.; Malamos, I.; Papadopoulos, C.G.; Verheyen, R. |
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Title |
Counting to one: reducibility of one- and two-loop amplitudes at the integrand level |
Type |
Journal Article |
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Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
038 - 24pp |
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Keywords |
QCD Phenomenology; NLO Computations |
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Abstract |
Calculation of amplitudes in perturbative quantum field theory involve large loop integrals. The complexity of those integrals, in combination with the large number of Feynman diagrams, make the calculations very difficult. Reduction methods proved to be very helpful, lowering the number of integrals that need to be actually calculated. Especially reduction at the integrand level improves the speed and set-up of these calculations. In this article we demonstrate, by counting the numbers of tensor structures and independent coefficients, how to write such relations at the integrand level for one-and two-loop amplitudes. We clarify their connection to the so-called spurious terms at one loop and discuss their structure in the two-loop case. This method is also applicable to higher loops, and the results obtained apply to both planar and non-planar diagrams. |
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Address |
[Kleiss, Ronald H. P.; Verheyen, Rob] Radboud Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands, Email: R.Kleiss@science.ru.nl; |
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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 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000313123800038 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1346 |
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| Permanent link to this record |
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Author |
Kittel, O.; Pilaftsis, A. |
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Title |
CP violation in correlated production and decay of unstable particles |
Type |
Journal Article |
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Year |
2012 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
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Volume |
856 |
Issue |
3 |
Pages |
682-697 |
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Keywords |
EPR correlation; Resonant CP violation; Collider phenomenology |
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Abstract |
We study resonant CP-violating Einstein-Podolsky-Rosen correlations that may take place in the production and decay of unstable scalar particles at high-energy colliders. We show that as a consequence of unitarity and CPT invariance of the S-matrix, in 2 -> 2 scatterings mediated by mixed scalar particles, at least three linearly independent decay matrices associated with the unstable scalar states are needed to obtain non-zero CP-odd observables that are also odd under C-conjugation. Instead, for the correlated production and decay of two unstable particle systems in 2 -> 4 processes, we find that only two independent decay matrices are sufficient to induce a net non-vanishing CP-violating phenomenon. As an application of this theorem, we present numerical estimates of CP asymmetries for the correlated production and decay of supersymmetric scalar top anti-top pairs at the LHC, and demonstrate that these could reach values of order one. As a byproduct of our analysis, we develop a novel spinorial trace technique, which enables us to efficiently evaluate lengthy expressions of squared amplitudes describing the resonant scalar transitions. |
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Address |
[Kittel, Olaf] Univ Granada, Dept Fis Teor & Cosmos, E-18071 Granada, Spain, Email: kittel@th.physik.uni-bonn.de |
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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 |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300028200004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
892 |
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Author |
Jung, M.; Li, X.Q.; Pich, A. |
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Title |
Exclusive radiative B-meson decays within the aligned two-Higgs-doublet model |
Type |
Journal Article |
| |
Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
10 |
Issue |
10 |
Pages |
063 - 33pp |
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Keywords |
Higgs Physics; Beyond Standard Model; B-Physics; CP violation |
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Abstract |
In the aligned two-Higgs-doublet model, the alignment of Yukawa matrices in flavour space guarantees the absence of tree-level flavour-changing neutral currents, while allowing at the same time for new sources of CP violation, implying potentially large effects in many low-energy processes. In this work we study the constraints from exclusive radiative B -> V gamma decays, where V denotes a light vector meson. The current experimental data on the CP-averaged branching ratios and the direct CP and isospin asymmetries are analyzed. It is found that, while the branching ratios and direct CP asymmetries do not constrain the parameter space much further compared to the inclusive B -> X-s,X-d gamma decays, complementary constraints can be obtained from the isospin asymmetries Delta(K*gamma) and Delta(rho gamma). In addition, correlations between the various observables in exclusive B -> V gamma and inclusive B -> X-s,X-d gamma decays are investigated in detail, and predictions are made for several so far unmeasured observables. |
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Address |
[Jung, Martin] Tech Univ Dortmund, Inst Phys, D-44221 Dortmund, Germany, Email: martin2.jung@tu-dortmund.de; |
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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 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000310851800004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1293 |
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| Permanent link to this record |
