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Author |
Aguilar, A.C.; Ferreira, M.N.; Papavassiliou, J. |
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Title  |
Gluon dynamics from an ordinary differential equation |
Type |
Journal Article |
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Year |
2021 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
81 |
Issue |
1 |
Pages |
54 - 20pp |
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Abstract |
We present a novel method for computing the nonperturbative kinetic term of the gluon propagator from an ordinary differential equation, whose derivation hinges on the central hypothesis that the regular part of the three-gluon vertex and the aforementioned kinetic term are related by a partial Slavnov-Taylor identity. The main ingredients entering in the solution are projection of the three-gluon vertex and a particular derivative of the ghost-gluon kernel, whose approximate form is derived from a Schwinger-Dyson equation. Crucially, the requirement of a pole-free answer determines the initial condition, whose value is calculated from an integral containing the same ingredients as the solution itself. This feature fixes uniquely, at least in principle, the form of the kinetic term, once the ingredients have been accurately evaluated. In practice, however, due to substantial uncertainties in the computation of the necessary inputs, certain crucial components need be adjusted by hand, in order to obtain self-consistent results. Furthermore, if the gluon propagator has been independently accessed from the lattice, the solution for the kinetic term facilitates the extraction of the momentum-dependent effective gluon mass. The practical implementation of this method is carried out in detail, and the required approximations and theoretical assumptions are duly highlighted. |
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Address |
[Aguilar, A. C.; Ferreira, M. N.] Univ Campinas UNICAMP, Inst Phys Gleb Wataghin, BR-13083859 Campinas, SP, Brazil, Email: aguilar@ifi.unicamp.br |
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Publisher |
Springer |
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English |
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Series Volume |
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Edition |
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ISSN |
1434-6044 |
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Conference |
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Notes |
WOS:000611993400002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4730 |
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Author |
HAWC Collaboration (Abeysekara, A.U. et al); Salesa Greus, F. |
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Title |
HAWC observations of the acceleration of very-high-energy cosmic rays in the Cygnus Cocoon |
Type |
Journal Article |
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Year |
2021 |
Publication |
Nature Astronomy |
Abbreviated Journal |
Nat. Astron. |
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Volume |
4 |
Issue |
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Pages |
465–471 |
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Keywords |
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Abstract |
Cosmic rays with energies up to a few PeV are known to be accelerated within the Milky Way(1,2). Traditionally, it has been presumed that supernova remnants were the main source of these very-high-energy cosmic rays(3,4), but theoretically it is difficult to accelerate protons to PeV energies(5,6) and observationally there simply is no evidence of the remnants being sources of hadrons with energies above a few tens of TeV7,8. One possible source of protons with those energies is the Galactic Centre region(9). Here, we report observations of 1-100 TeV gamma rays coming from the 'Cygnus Cocoon'(10), which is a superbubble that surrounds a region of massive star formation. These gamma rays are likely produced by 10-1,000 TeV freshly accelerated cosmic rays that originate from the enclosed star-forming region Cyg OB2. Until now it was not known that such regions could accelerate particles to these energies. The measured flux likely originates from hadronic interactions. The spectral shape and the emission profile of the Cocoon changes from GeV to TeV energies, which reveals the transport of cosmic particles and historical activity in the superbubble. |
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Address |
[Abeysekara, A. U.; Hona, B.; Kieda, D.; Newbold, M.; Springer, R. W.] Univ Utah, Dept Phys & Astron, Salt Lake City, UT 84112 USA, Email: rdb3@stanford.edu; |
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Publisher |
Nature Research |
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Language |
English |
Summary Language |
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Original Title |
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Edition |
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ISSN |
2397-3366 |
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Conference |
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Notes |
WOS:000627714400002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4763 |
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Author |
HAWC Collaboration (Albert, A. et al); Salesa Greus, F. |
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Title |
HAWC Search for High-mass Microquasars |
Type |
Journal Article |
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Year |
2021 |
Publication |
Astrophysical Journal Letters |
Abbreviated Journal |
Astrophys. J. Lett. |
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Volume |
912 |
Issue |
1 |
Pages |
L4 - 12pp |
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Keywords |
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Abstract |
Microquasars with high-mass companion stars are promising very high energy (VHE; 0.1-100 TeV) gamma-ray emitters, but their behaviors above 10 TeV are poorly known. Using the High Altitude Water Cerenkov (HAWC) observatory, we search for excess gamma-ray emission coincident with the positions of known high-mass microquasars (HMMQs). No significant emission is observed for LS 5039, Cyg X-1, Cyg X-3, and SS 433 with 1523 days of HAWC data. We set the most stringent limit above 10 TeV obtained to date on each individual source. Under the assumption that HMMQs produce gamma rays via a common mechanism, we have performed source-stacking searches, considering two different scenarios: (I) gamma-ray luminosity is a fraction epsilon ( gamma ) of the microquasar jet luminosity, and (II) VHE gamma rays are produced by relativistic electrons upscattering the radiation field of the companion star in a magnetic field B. We obtain epsilon ( gamma ) < 5.4 x 10(-6) for scenario I, which tightly constrains models that suggest observable high-energy neutrino emission by HMMQs. In the case of scenario II, the nondetection of VHE gamma rays yields a strong magnetic field, which challenges synchrotron radiation as the dominant mechanism of the microquasar emission between 10 keV and 10 MeV. |
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Address |
[Albert, A.; Dingus, B. L.; Durocher, M.; Harding, J. P.; Malone, K.] Los Alamos Natl Lab, Div Phys, Los Alamos, NM 87545 USA, Email: kefang@physics.wisc.edu; |
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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 |
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Series Issue |
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Edition |
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ISSN |
2041-8205 |
ISBN |
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Area |
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Conference |
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Notes |
WOS:000646368700001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4798 |
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Author |
Cottin, G.; Helo, J.C.; Hirsch, M.; Titov, A.; Wang, Z.S. |
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Title |
Heavy neutral leptons in effective field theory and the high-luminosity LHC |
Type |
Journal Article |
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Year |
2021 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
09 |
Issue |
9 |
Pages |
039 - 34pp |
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Keywords |
Beyond Standard Model; Effective Field Theories; Neutrino Physics |
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Abstract |
Heavy neutral leptons (HNLs) with masses around the electroweak scale are expected to be rather long-lived particles, as a result of the observed smallness of the active neutrino masses. In this work, we study long-lived HNLs in NRSMEFT, a Standard Model (SM) extension with singlet fermions to which we add non-renormalizable operators up to dimension-6. Operators which contain two HNLs can lead to a sizable enhancement of the production cross sections, compared to the minimal case where HNLs are produced only via their mixing with the SM neutrinos. We calculate the expected sensitivities for the ATLAS detector and the future far-detector experiments: AL3X, ANUBIS, CODEX-b, FASER, MATHUSLA, and MoEDAL-MAPP in this setup. The sensitive ranges of the HNL mass and of the active-heavy mixing angle are much larger than those in the minimal case. We study both, Dirac and Majorana, HNLs and discuss how the two cases actually differ phenomenologically, for HNL masses above roughly 100 GeV. |
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Address |
[Cottin, Giovanna] Univ Adolfo Ibanez, Fac Artes Liberales, Dept Ciencias, Diagonal Las Torres 2640, Santiago, Chile, Email: giovanna.cottin@uai.cl; |
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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 |
1029-8479 |
ISBN |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000694840800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4970 |
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Author |
Monerris-Belda, O.; Cervera Marin, R.; Rodriguez Jodar, M.; Diaz-Caballero, E.; Alcaide Guillen, C.; Petit, J.; Boria, V.E.; Gimeno, B.; Raboso, D. |
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Title |
High Power RF Discharge Detection Technique Based on the In-Phase and Quadrature Signals |
Type |
Journal Article |
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Year |
2021 |
Publication |
IEEE Transactions on Microwave Theory and Techniques |
Abbreviated Journal |
IEEE Trans. Microw. Theory Tech. |
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Volume |
69 |
Issue |
12 |
Pages |
5429-5438 |
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Keywords |
Radio frequency; Microwave theory and techniques; Electric breakdown; Discharges (electric); Noise measurement; Sensitivity; RF signals; Corona; microwave devices; multipactor; radio frequency (RF) breakdown; RF high power |
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Abstract |
High power radio frequency (RF) breakdown testing is a subject of great relevance in the space industry, due to the increasing need of higher transmission power and smaller devices. This work presents a novel RF breakdown detection system, which monitors the same parameters as the microwave nulling system but with several advantages. Where microwave nulling-a de facto standard in RF breakdown testing-is narrowband and requires continuous tuning to keep its sensitivity, the proposed technique is broadband and maintains its performance for any RF signal. On top of that, defining the detection threshold is cumbersome due to the lack of an international standardized criterion. Small responses may appear in the detection system during the test and, sometimes, it is not possible to determine if these are an actual RF breakdown or random noise. This new detection system uses a larger analysis bandwidth, thus reducing the cases in which a small response is difficult to be classified. The proposed detection method represents a major step forward in high power testing as it runs without human intervention, warning the operator or decreasing the RF power automatically much faster than any human operator. |
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Address |
[Monerris-Belda, Oscar; Cervera Marin, Raul; Rodriguez Jodar, Miguel; Petit, John] Val Space Consortium, Valencia 46022, Spain, Email: oscar.monerris@val-space.com |
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Corporate Author |
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Thesis |
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Publisher |
Ieee-Inst Electrical Electronics Engineers Inc |
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 |
0018-9480 |
ISBN |
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Conference |
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Notes |
WOS:000725804500027 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5042 |
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