| |
Records |
Links |
|
Author |
Barenboim, G.; Chen, J.Z.; Hannestad, S.; Oldengott, I.M.; Tram, T.; Wong, Y.Y.Y. |
|
| |
Title |
Invisible neutrino decay in precision cosmology |
Type |
Journal Article |
| |
Year |
2021 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
|
| |
Volume |
03 |
Issue |
3 |
Pages |
087 - 53pp |
|
| |
Keywords |
cosmological neutrinos; neutrino properties; CMBR theory; cosmological parameters from CMBR |
|
| |
Abstract  |
We revisit the topic of invisible neutrino decay in the precision cosmological context, via a first-principles approach to understanding the cosmic microwave background and large-scale structure phenomenology of such a non-standard physics scenario. Assuming an effective Lagrangian in which a heavier standard-model neutrino nu(H) couples to a lighter one nu(l) and a massless scalar particle phi via a Yukawa interaction, we derive from first principles the complete set of Boltzmann equations, at both the spatially homogeneous and the firstorder inhomogeneous levels, for the phase space densities of nu(H), nu(l), and phi in the presence of the relevant decay and inverse decay processes. With this set of equations in hand, we perform a critical survey of recent works on cosmological invisible neutrino decay in both limits of decay while nu(H) is ultra-relativistic and non-relativistic. Our two main findings are: (i) in the non-relativistic limit, the effective equations of motion used to describe perturbations in the neutrino-scalar system in the existing literature formally violate momentum conservation and gauge invariance, and (ii) in the ultra-relativistic limit, exponential damping of the anisotropic stress does not occur at the commonly-used rate Gamma(T) = (1/tau(0))( m(nu H)/E-nu H)(3), but at a rate similar to (1/ tau(0))(m(nu H)/E-nu H)(5). Both results are model-independent. The impact of the former finding on the cosmology of invisible neutrino decay is likely small. The latter, however, implies a significant revision of the cosmological limit on the neutrino lifetime tau(0) from tau(old)(0) greater than or similar to 1.2 x 10(9) s (m(nu H)/50 meV)(3) to tau(0) greater than or similar to (4 x 10(5) -> 4 x 10(6)) s (m(nu H)/50 meV)(5). |
|
| |
Address |
[Barenboim, Gabriela; Oldengott, Isabel M.] Univ Valencia, Dept Fis Teor, CSIC, Burjassot 46100, Spain, Email: gabriela.barenboim@uv.es; |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Iop Publishing Ltd |
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1475-7516 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
WOS:000636717400082 |
Approved |
no |
|
| |
Is ISI |
yes |
International Collaboration |
yes |
|
| |
Call Number |
IFIC @ pastor @ |
Serial |
4782 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Hernandez, P.; Romero-Lopez, F. |
|
| |
Title |
The large N-c limit of QCD on the lattice |
Type |
Journal Article |
| |
Year |
2021 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
|
| |
Volume |
57 |
Issue |
2 |
Pages |
52 - 19pp |
|
| |
Keywords |
|
|
| |
Abstract |
We review recent progress in the study of the large N-c limit of gauge theories from lattice simulations. The focus is not only the planar limit but also the size of O(N-c(-1)) corrections for values of N-c greater than or similar to 3. Some concrete examples of the topics we include are tests of large- Nc factorization, the topological susceptibility, the glueball, meson and baryon spectra, the chiral dependence of masses and decay constants, and weak matrix elements related to the Delta I = 1/2 rule in kaon decays. |
|
| |
Address |
[Romero-Lopez, Fernando] Univ Valencia, Inst Fis Corpuscular, Valencia, Spain, Email: m.pilar.hernandez@uv.es; |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Springer |
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1434-6001 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
WOS:000617515000003 |
Approved |
no |
|
| |
Is ISI |
yes |
International Collaboration |
no |
|
| |
Call Number |
IFIC @ pastor @ |
Serial |
4718 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
NA64 Collaboration (Cazzaniga, C. et al); Molina Bueno, L. |
|
| |
Title |
Probing the explanation of the muon (g-2) anomaly and thermal light dark matter with the semi-visible dark photon channel |
Type |
Journal Article |
| |
Year |
2021 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
|
| |
Volume |
81 |
Issue |
10 |
Pages |
959 - 6pp |
|
| |
Keywords |
|
|
| |
Abstract |
We report the results of a search for a new vector boson (A') decaying into two dark matter particles chi 1 chi 2 of different mass. The heavier chi(2) particle subsequently decays to chi 1 and an off-shell Dark Photon A'* -> e(+)e(-). For a sufficiently largemass splitting, this model can explain in terms of new physics the recently confirmed discrepancy observed in themuon anomalous magnetic moment at Fermilab. Remark- ably, it also predicts the observed yield of thermal dark matter relic abundance. A detailed Monte-Carlo simulation was used to determine the signal yield and detection efficiency for this channel in the NA64 setup. The results were obtained reanalyzing the previous NA64 searches for an invisible decay A' -> chi(chi) over bar and axion-like or pseudo-scalar particles -> gamma gamma. With this method, we exclude a significant portion of the parameter space justifying the muon g-2 anomaly and being compatible with the observed dark matter relic density for A' masses from 2m(e) up to 390 MeV and mixing parameter e between 3 x 10(-5) and 2 x 10(-2). |
|
| |
Address |
[Cazzaniga, C.; Odagiu, P.; Depero, E.; Bueno, L. Molina; Crivelli, P.; Radics, B.; Rubbia, A.; Sieber, H.] Swiss Fed Inst Technol, Inst Particle Phys & Astrophys, CH-8093 Zurich, Switzerland, Email: Paolo.Crivelli@cern.ch |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Springer |
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
1434-6044 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
WOS:000712961200001 |
Approved |
no |
|
| |
Is ISI |
yes |
International Collaboration |
yes |
|
| |
Call Number |
IFIC @ pastor @ |
Serial |
5013 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
NA64 Collaboration (Andreev, Y.M. et al); Molina Bueno, L. |
|
| |
Title |
Search for pseudoscalar bosons decaying into e(+)e(-) pairs in the NA64 experiment at the CERN SPS |
Type |
Journal Article |
| |
Year |
2021 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
|
| |
Volume |
104 |
Issue |
11 |
Pages |
L111102 - 5pp |
|
| |
Keywords |
|
|
| |
Abstract |
We report the results of a search for a light pseudoscalar particle a that couples to electrons and decays to e(+) e(-) perfbnned using the high-energy CERN SPS H4 electron beam. If such light pseudoscalar exists, it could explain the ATOMKI anomaly (an excess of e(+) e(-) pairs in the nuclear transitions of Be-8 and 4 He nuclei at the invariant mass similar or equal to 17 MeV observed by the experiment at the 5 MV Van de Graaff accelerator at ATOMKI, Hungary). We used the NA64 data collected in the “visible mode” configuration with a total statistics corresponding to 8.4 x 10(10) electrons on target (EOT) in 2017 and 2018. In order to increase sensitivity to small coupling parameter epsilon we also used the data collected in 2016-2018 in the “invisible mode” configuration of NA64 with a total statistics corresponding to 2.84 x 10(11) EOT. The background and efficiency estimates for these two configurations were retained from our previous analyses searching for light vector bosons and axionlike particles (ALP) (the latter were assumed to couple predominantly to gamma). In this work we recalculate the signal yields, which are different due to different cross section and lifetime of a pseudoscalar particle a, and perform a new statistical analysis. As a result, the region of the two dimensional parameter space m(a) – epsilon in the mass range from 1 to 17.1 MeV is excluded. At the mass of the central value of the ATOMKI anomaly (the first result obtained on the beryllium nucleus, 16.7 MeV) the values of epsilon in the range 2.1 x 10(-4) < epsilon < 3.2 x 10(-4) are excluded. |
|
| |
Address |
[Hoesgen, M.; Ketzer, B.] Univ Bonn, Helmholtz Inst Strahlen & Kernphys, D-53115 Bonn, Germany |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2470-0010 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
WOS:000738796900005 |
Approved |
no |
|
| |
Is ISI |
yes |
International Collaboration |
yes |
|
| |
Call Number |
IFIC @ pastor @ |
Serial |
5071 |
|
| Permanent link to this record |
| |
|
| |
|
Author |
Hafner, G. et al; Algora, A. |
|
| |
Title |
First lifetime investigations of N > 82 iodine isotopes: The quest for collectivity |
Type |
Journal Article |
| |
Year |
2021 |
Publication |
Physical Review C |
Abbreviated Journal |
Phys. Rev. C |
|
| |
Volume |
104 |
Issue |
1 |
Pages |
014316 - 18pp |
|
| |
Keywords |
|
|
| |
Abstract |
We report on spectroscopic information and lifetime measurements in the neutron-rich I-135,I-137,I-139 isotopes. This is the first lifetime data on iodine isotopes beyond N = 82. Excited states were populated in fast neutron-induced fission of U-238 at the ALTO facility of IJCLab with the LICORNE neutron source and detected using the hybrid nu-ball spectrometer. The level schemes of the I-135,I-137,I-139 isotopes are revised in terms of excited states with up to maximum spin-parity of (33/2(+)), populated for the first time in fast neutron-induced fission. We provide first results on the lifetimes of the (9/2(1)(+)) and (13/2(1)(+)) states in I-137 and I-139, and the (17/2(1)(+)) state in 137I. In addition, we give upper lifetime limits for the (11/2(1)(+)) states in I135-139, the (15/2(1)(+)) state in I-137, the (17/2(1)(+)) state in I-139, and reexamine the (29/2(1)(+)) state in I-137. The isomeric data in I-13(5) are reinvestigated, such as the previously known (15/2(1)(+)) and (23/21) isomers with T-1/2 of 1.64(14) and 4.6(7) ns, respectively, as obtained in this work. The new spectroscopic information is compared to that from spontaneous or thermal-neutron induced fission and discussed in the context of large scale shell-model (LSSM) calculations for the region beyond Sn-132, indicating the behavior of collectivity for the three valence-proton iodine chain with N = 82, 84, 86. |
|
| |
Address |
[Haefner, G.; Lozeva, R.; Lebois, M.; Jovancevic, N.; Thisse, D.; Wilson, J. N.; Babo, M.; Chakma, R.; Delafosse, C.; Hauschild, K.; Ibrahim, F.; Nemer, J.; Popovitch, Y.; Qi, L.; Ralet, D.; Tocabens, G.; Verney, D.] Univ Paris Saclay, IJCLab, CNRS IN2P3, F-91405 Orsay, France, Email: radomira.lozeva@ijclab.in2p3.fr |
|
| |
Corporate Author |
|
Thesis |
|
|
| |
Publisher |
Amer Physical Soc |
Place of Publication |
|
Editor |
|
|
| |
Language |
English |
Summary Language |
|
Original Title |
|
|
| |
Series Editor |
|
Series Title |
|
Abbreviated Series Title |
|
|
| |
Series Volume |
|
Series Issue |
|
Edition |
|
|
| |
ISSN |
2469-9985 |
ISBN |
|
Medium |
|
|
| |
Area |
|
Expedition |
|
Conference |
|
|
| |
Notes |
WOS:000674546900001 |
Approved |
no |
|
| |
Is ISI |
yes |
International Collaboration |
yes |
|
| |
Call Number |
IFIC @ pastor @ |
Serial |
4913 |
|
| Permanent link to this record |
