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Author  |
Boito, D.; Cata, O.; Golterman, M.; Jamin, M.; Maltman, K.; Osborne, J.; Peris, S. |
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Title |
New determination of alpha(s) from hadronic tau decays |
Type |
Journal Article |
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Year |
2011 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
84 |
Issue |
11 |
Pages |
113006 - 19pp |
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Abstract |
We present a new framework for the extraction of the strong coupling from hadronic tau decays through finite-energy sum rules. Our focus is on the small, but still significant nonperturbative effects that, in principle, affect both the central value and the systematic error. We employ a quantitative model in order to accommodate violations of quark-hadron duality, and enforce a consistent treatment of the higher-dimensional contributions of the operator product expansion to our sum rules. Using 1998 OPAL data for the nonstrange isovector vector and axial-vector spectral functions, we find the n(f) = 3 values alpha(s)(m(tau)(2)) = 0.307 +/- 0.019 in fixed-order perturbation theory, and 0.322 +/- 0.026 in contour-improved perturbation theory. For comparison, the original OPAL analysis of the same data led to the values 0.324 +/- 0.014 (fixed order) and 0.348 +/- 0.021 (contour improved). |
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Address |
[Boito, Diogo] Univ Autonoma Barcelona, Dept Fis, E-08193 Barcelona, Spain |
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Publisher |
Amer Physical Soc |
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English |
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Edition |
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ISSN |
1550-7998 |
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Notes |
WOS:000298131000001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
847 |
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Author |
Keivani, A.; Murase, K.; Petropoulou, M.; Fox, D.B.; Cenko, S.B.; Chaty, S.; Coleiro, A.; DeLaunay, J.J.; Dimitrakoudis, S.; Evans, P.A.; Kennea, J.A.; Marshall, F.E.; Mastichiadis, A.; Osborne, J.P.; Santander, M.; Tohuvavohu, A.; Turley, C.F. |
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Title |
A Multimessenger Picture of the Flaring Blazar TXS 0506+056: Implications for High-energy Neutrino Emission and Cosmic-Ray Acceleration |
Type |
Journal Article |
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Year |
2018 |
Publication |
Astrophysical Journal |
Abbreviated Journal |
Astrophys. J. |
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Volume |
864 |
Issue |
1 |
Pages |
84 - 16pp |
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Keywords |
Lacertae objects: general; BL Lacertae objects: individual (TXS 0506+056); galaxies: active; gamma rays: galaxies; neutrinos; radiation mechanisms: non-thermal |
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Abstract |
Detection of the IceCube-170922A neutrino coincident with the flaring blazar TXS 0506+056, the first and only similar to 3 sigma high-energy neutrino source association to date, offers a potential breakthrough in our understanding of high-energy cosmic particles and blazar physics. We present a comprehensive analysis of TXS. 0506+056 during its flaring state, using newly collected Swift, NuSTAR, and X-shooter data with Fermi observations and numerical models to constrain the blazar's particle acceleration processes and multimessenger (electromagnetic (EM) and high-energy neutrino) emissions. Accounting properly for EM cascades in the emission region, we find a physically consistent picture only within a hybrid leptonic scenario, with gamma-rays produced by external inverse-Compton processes and high-energy neutrinos via a radiatively subdominant hadronic component. We derive robust constraints on the blazar's neutrino and cosmic-ray emissions and demonstrate that, because of cascade effects, the 0.1-100 keV emissions of TXS. 0506+056 serve as a better probe of its hadronic acceleration and highenergy neutrino production processes than its GeV-TeV emissions. If the IceCube neutrino association holds, physical conditions in the TXS. 0506+056 jet must be close to optimal for high-energy neutrino production, and are not favorable for ultrahigh-energy cosmic-ray acceleration. Alternatively, the challenges we identify in generating a significant rate of IceCube neutrino detections from TXS. 0506+056 may disfavor single-zone models, in which.-rays and high-energy neutrinos are produced in a single emission region. In concert with continued operations of the high-energy neutrino observatories, we advocate regular X-ray monitoring of TXS. 0506+056 and other blazars in order to test single-zone blazar emission models, clarify the nature and extent of their hadronic acceleration processes, and carry out the most sensitive possible search for additional multimessenger sources. |
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Address |
[Keivani, A.; Murase, K.; DeLaunay, J. J.; Turley, C. F.] Penn State Univ, Dept Phys, 104 Davey Lab, University Pk, PA 16802 USA, Email: keivani@psu.edu; |
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Corporate Author |
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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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Abbreviated Series Title |
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ISSN |
0004-637x |
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Conference |
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Notes |
WOS:000443293800010 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3708 |
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