| Records |
| Author |
Cappiello, L.; Cata, O.; D'Ambrosio, G. |
| Title |
Hadronic light by light contribution to the (g-2)(mu) with holographic models of QCD |
Type |
Journal Article |
| Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal  |
Phys. Rev. D |
| Volume |
83 |
Issue |
9 |
Pages |
093006 - 19pp |
| Keywords |
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| Abstract |
We study the anomalous electromagnetic pion form factor F-pi 0 gamma*gamma* with a set of holographic models. By comparing with the measured value of the linear slope, some of these models can be ruled out. From the remaining models, we obtain predictions for the low-energy quadratic slope parameters of F-pi 0 gamma*gamma* , currently out of experimental reach but testable in the near future. We find it particularly useful to encode this low-energy information in a form factor able to satisfy also QCD short-distance constraints. We choose the form factor introduced by D'Ambrosio, Isidori, and Portoles in kaon decays, which has the right short distance for a particular value of the quadratic slope, which is later shown to be compatible with our holographic predictions. We then turn to a determination of the (dominant) pion exchange diagram in the hadronic light by light scattering contribution to the muon anomalous magnetic moment. We quantify the theoretical uncertainty in (g – 2)(mu) coming from the different input we use: QCD short distances, experimental input, and low-energy holographic predictions. We also test the pion-pole approximation. Our final result is a(mu)(pi 0) = 6: 54(25) x 10(-10), where the error is driven by the linear slope of F-pi 0 gamma*gamma* , soon to be measured with precision at KLOE-2. Our numerical analysis also indicates that large values of the magnetic susceptibility chi 0 are disfavored, therefore pointing at a mild effect from the pion off-shellness. However, in the absence of stronger bounds on chi 0, an additional (10-15)% systematic uncertainty on the previous value for a(mu)(pi 0) cannot be excluded. |
| Address |
[Cappiello, Luigi] Univ Naples Federico 2, Dipartimento Sci Fis, I-80126 Naples, Italy |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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| Language |
English |
Summary Language |
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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 |
ISI:000290479200002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
625 |
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| Author |
BABAR Collaboration (del Amo Sanchez, P. et al); Lopez-March, N.; Martinez-Vidal, F.; Oyanguren, A. |
| Title |
Measurement of the B-0 -> pi(-)l(+)nu and B+ -> eta(l)l(+)nu branching fractions, the B-0 -> pi(-)l(+)nu and B+ -> eta l(+)nu form- factor shapes, and determination of |Vub| |
Type |
Journal Article |
| Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
83 |
Issue |
5 |
Pages |
052011 - 16pp |
| Keywords |
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| Abstract |
We report the results of a study of the exclusive charmless semileptonic decays, B+ -> eta(l)l(+)nu and B-0 -> pi(-)l(+)nu undertaken with approximately 464 x 10(6) B (B) over bar pairs collected at the Y(4S) resonance with the BABAR detector. The analysis uses events in which the signal B decays are reconstructed with a loose neutrino reconstruction technique. We obtain partial branching fractions for B+ -> eta l(+)nu and B-0 -> pi(-)l(+)nu decays in three and 12 bins of q(2), respectively, from which we extract the f (+)(q(2)) form-factor shapes and the total branching fractions B(B+ -> eta l(+)nu)= (0.36 +/- 0.05(stat) +/- 0.04(syst)) x 10(-4) and B(B-0 -> pi(-)l(+)nu) = (1.42 +/- 0.05(stat) +/- 0.07(syst)) x 10(-4). We also measure B(B+ -> eta'l(+)nu) = (0.24 +/- 0.08(stat) +/- 0.03(syst)) x 10(-4). We obtain values for the magnitude of the CKM matrix element |V-ub| using three different QCD calculations. |
| Address |
[Sanchez, P. del Amo; Lees, J. P.; Poireau, V.; Prencipe, E.; Tisserand, V.] Univ Savoie, Lab Annecy Le Vieux Phys Particules, CNRS, IN2P3, F-74941 Annecy Le Vieux, France |
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Thesis |
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| Publisher |
Amer Physical Soc |
Place of Publication |
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English |
Summary Language |
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1550-7998 |
ISBN |
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Medium |
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Expedition |
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Conference |
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| Notes |
ISI:000288787100002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
537 |
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| Author |
Escrihuela, F.J.; Tortola, M.; Valle, J.W.F.; Miranda, O.G. |
| Title |
Global constraints on muon-neutrino nonstandard interactions |
Type |
Journal Article |
| Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
83 |
Issue |
9 |
Pages |
093002 - 8pp |
| Keywords |
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| Abstract |
The search for new interactions of neutrinos beyond those of the standard model may help to elucidate the mechanism responsible for neutrino masses. Here, we combine existing accelerator neutrino data with restrictions coming from a recent atmospheric neutrino data analysis in order to lift parameter degeneracies and improve limits on new interactions of muon neutrinos with quarks. In particular, we reconsider the results of the E-815 experiment at Fermilab (NuTeV) in view of a new evaluation of its systematic uncertainties. We find that, although constraints for muon neutrinos are better than those applicable to tau or electron neutrinos, they lie at the few X 10(-2) level, not as strong as previously believed. We briefly discuss prospects for further improvement. |
| Address |
[Escrihuela, F. J.; Tortola, M.; Valle, J. W. F.] Univ Politecn Valencia, CSIC, Inst Fis Corpuscular, E-46071 Valencia, Spain, Email: franesfe@alumni.uv.es |
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| Publisher |
Amer Physical Soc |
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English |
Summary Language |
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Abbreviated Series Title |
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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 |
ISI:000290230200002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
616 |
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| Author |
Esteves, J.N.; Romao, J.C.; Hirsch, M.; Staub, F.; Porod, W. |
| Title |
Supersymmetric type-III seesaw mechanism: Lepton flavor violating decays and dark matter |
Type |
Journal Article |
| Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
83 |
Issue |
1 |
Pages |
013003 - 21pp |
| Keywords |
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| Abstract |
We study a supersymmetric version of the seesaw mechanism type III. The model consists of the minimal supersymmetric extension of the standard model particle content plus three copies of 24 superfields. The fermionic part of the SU(2) triplet contained in the 24 is responsible for the type-III seesaw, which is used to explain the observed neutrino masses and mixings. Complete copies of 24 are introduced to maintain gauge coupling unification. These additional states change the beta functions of the gauge couplings above the seesaw scale. Using minimal Supergravity boundary conditions, we calculate the resulting supersymmetric mass spectra at the electroweak scale using full 2-loop renormalization group equations. We show that the resulting spectrum can be quite different compared to the usual minimal Supergravity spectrum. We discuss how this might be used to obtain information on the seesaw scale from mass measurements. Constraints on the model space due to limits on lepton flavour violating decays are discussed. The main constraints come from the bounds on μ-> e gamma but there are also regions where the decay tau -> μgamma gives stronger constraints. We also calculate the regions allowed by the dark matter constraint. For the sake of completeness, we compare our results with those for the supersymmetric seesaw type II and, to some extent, with type I. |
| Address |
[Esteves, J. N.; Romao, J. C.] Inst Super Tecn, Dept Fis, P-1049001 Lisbon, Portugal, Email: joaomest@cftp.ist.utl.pt |
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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 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 |
ISI:000286765100002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
583 |
| Permanent link to this record |
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| Author |
Aguilar, A.C.; Papavassiliou, J. |
| Title |
Chiral symmetry breaking with lattice propagators |
Type |
Journal Article |
| Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
83 |
Issue |
1 |
Pages |
014013 - 17pp |
| Keywords |
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| Abstract |
We study chiral symmetry breaking using the standard gap equation, supplemented with the infrared-finite gluon propagator and ghost dressing function obtained from large-volume lattice simulations. One of the most important ingredients of this analysis is the non-Abelian quark-gluon vertex, which controls the way the ghost sector enters into the gap equation. Specifically, this vertex introduces a numerically crucial dependence on the ghost dressing function and the quark-ghost scattering amplitude. This latter quantity satisfies its own, previously unexplored, dynamical equation, which may be decomposed into individual integral equations for its various form factors. In particular, the scalar form factor is obtained from an approximate version of the “one-loop dressed” integral equation, and its numerical impact turns out to be rather considerable. The detailed numerical analysis of the resulting gap equation reveals that the constituent quark mass obtained is about 300 MeV, while fermions in the adjoint representation acquire a mass in the range of (750-962) MeV. |
| Address |
[Aguilar, A. C.] Fed Univ ABC, CCNH, BR-09210170 Santo Andre, Brazil, Email: Arlene.Aguilar@ufabc.edu.br |
| Corporate Author |
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Thesis |
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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 |
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 |
ISI:000286765100005 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
584 |
| Permanent link to this record |
