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Author |
Cepedello, R.; Deppisch, F.F.; Gonzalez, L.; Hati, C.; Hirsch, M. |
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Title  |
Neutrinoless Double-Beta Decay with Nonstandard Majoron Emission |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physical Review Letters |
Abbreviated Journal |
Phys. Rev. Lett. |
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Volume |
122 |
Issue |
18 |
Pages |
181801 - 6pp |
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Keywords |
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Abstract |
We present a novel mode of neutrinoless double-beta decay with emission of a light Majoron-like scalar particle phi. We assume it couples via an effective seven-dimensional operator with a (V + A) lepton current and (V +/- A) quark currents leading to a long-range contribution that is unsuppressed by the light neutrino mass. We calculate the total double-beta decay rate and determine the fully differential shape for this mode. We find that future double-beta decay searches are sensitive to scales of the order Lambda(NP) approximate to 1 TeV for the effective operator and a light scalar m(phi) < 0.2 MeV, based on ordinary double-beta decay Majoron searches. The angular and energy distributions can deviate considerably from that of two-neutrino double-beta decay, which is the main background. We point out possible ultraviolet completions where such an effective operator can emerge. |
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Address |
[Cepedello, Ricardo; Hirsch, Martin] Univ Valencia, CSIC, Inst Fis Corpuscular, AHEP Grp, Edificio Inst Paterna,Apartado 22085, E-46071 Valencia, Spain, Email: ricepe@ific.uv.es; |
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Publisher |
Amer Physical Soc |
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Language |
English |
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ISSN |
0031-9007 |
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Conference |
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Notes |
WOS:000467042800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4002 |
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Author |
Soderstrom, P.A. et al; Agramunt, J.; Egea, J.; Gadea, A.; Huyuk, T. |
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Title |
Neutron detection and gamma-ray suppression using artificial neural networks with the liquid scintillators BC-501A and BC-537 |
Type |
Journal Article |
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Year |
2019 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
916 |
Issue |
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Pages |
238-245 |
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Keywords |
BC-501A; BC-537; Digital pulse-shape discrimination; Fast-neutron detection; Liquid scintillator; Neural networks |
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Abstract |
In this work we present a comparison between the two liquid scintillators BC-501A and BC-537 in terms of their performance regarding the pulse-shape discrimination between neutrons and gamma rays. Special emphasis is put on the application of artificial neural networks. The results show a systematically higher gamma-ray rejection ratio for BC-501A compared to BC-537 applying the commonly used charge comparison method. Using the artificial neural network approach the discrimination quality was improved to more than 95% rejection efficiency of gamma rays over the energy range 150 to 1000 keV for both BC-501A and BC-537. However, due to the larger light output of BC-501A compared to BC-537, neutrons could be identified in BC-501A using artificial neural networks down to a recoil proton energy of 800 keV compared to a recoil deuteron energy of 1200 keV for BC-537. We conclude that using artificial neural networks it is possible to obtain the same gamma-ray rejection quality from both BC-501A and BC-537 for neutrons above a low-energy threshold. This threshold is, however, lower for BC-501A, which is important for nuclear structure spectroscopy experiments of rare reaction channels where low-energy interactions dominates. |
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Address |
[Soderstrom, P-A] ELI NP, Bucharest 077125, Romania, Email: par.anders@eli-np.ro |
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Publisher |
Elsevier Science Bv |
Place of Publication |
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Language |
English |
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ISSN |
0168-9002 |
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Notes |
WOS:000455016800033 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3869 |
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Author |
Wang, Y.F.; Yao, D.L.; Zheng, H.Q. |
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Title |
New insights on low energy pi N scattering amplitudes: comprehensive analyses at O (p(3)) level |
Type |
Journal Article |
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Year |
2019 |
Publication |
Chinese Physics C |
Abbreviated Journal |
Chin. Phys. C |
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Volume |
43 |
Issue |
6 |
Pages |
064110 - 22pp |
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Keywords |
dispersion relations; pion-nucleon scattering; chiral perturbation theory |
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Abstract |
A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the O (p(3)) results obtained in covariant baryon chiral perturbation theory within the extendedon-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in S-11 and P-11 channels, as conjectured in our previous paper [Eur. Phys. J. C, 78(7): 543 (2018)], are firmly established. Specifically, the pole mass of the S-11 hidden resonance is determined to be (895 +/- 81)-(164 +/- 23)i MeV, whereas, the virtual pole in the P-11 channel locates at (966 +/- 18) MeV. It is found that analyses at the O (p(3)) level improves significantly the fit quality, comparing with the previous O (p(2)) one. Quantitative studies with cautious physical discussions are also conducted for the other S- and P-wave channels. |
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Address |
[Wang, Yu-Fei; Zheng, Han-Qing] Peking Univ, Dept Phys, Beijing 100871, Peoples R China, Email: yaodeliang@pku.edu.cn |
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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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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 |
1674-1137 |
ISBN |
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Conference |
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Notes |
WOS:000468501700013 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4020 |
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Author |
Watanabe, H. et al; Montaner-Piza, A. |
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Title |
New isomers in (125)Pd(79)( )and Pd-127(81): Competing proton and neutron excitations in neutron-rich palladium nuclides towards the N=82 shell closure |
Type |
Journal Article |
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Year |
2019 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
792 |
Issue |
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Pages |
263-268 |
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Keywords |
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Abstract |
The neutron-rich isotopes of palladium have attracted considerable interest in terms of the evolution of the N = 82 neutron shell closure and its influence on the r-process nucleosynthesis. In this Letter, we present the first spectroscopic information on the excited states in Pd-125(79) and Pd-127(81) studied using the EURICA gamma-ray spectrometer, following production via in-flight fission of a high-intensity U-238 beam at the RIBF facility. New isomeric states with half-lives of 144(4) ns and 39(6) μs have been assigned spins and parities of (23/2(+)) and (19/2(+)) in Pd-125 and Pd-127, respectively. The observed level properties are compared to a shell-model calculation, suggesting the competition between proton excitations and neutron excitations in the proton-hole and neutron-hole systems in the vicinity of the doubly magic nucleus Sn-132. |
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Address |
[Watanabe, H.] Beihang Univ, Sch Phys & Nucl Energy Engn, Beijing 100191, Peoples R China, Email: hiroshi@ribf.riken.jp |
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Corporate Author |
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Thesis |
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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 |
0370-2693 |
ISBN |
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Conference |
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Notes |
WOS:000466802100040 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3998 |
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Author |
Xu, S.S.; Cui, Z.F.; Chang, L.; Papavassiliou, J.; Roberts, C.D.; Zong, H.S. |
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Title |
New perspective on hybrid mesons |
Type |
Journal Article |
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Year |
2019 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
55 |
Issue |
7 |
Pages |
113 - 6pp |
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Keywords |
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Abstract |
We introduce a novel approach to the hybrid-meson (valence-gluon+quark+antiquark) bound-state problem in relativistic quantum field theory. Exploiting the existence of strong two-body correlations in the gluon-quark, q(g) = [gq], and gluon-antiquark, (q) over bar (g) = [g (q) over bar] channels, we argue that a sound description of hybrids can be obtained by solving a coupled pair of effectively two-body equations; and, consequently, that hybrids may be viewed as highly correlated q(g)(q) over bar <-> q (q) over bar (g) bound states. Analogies may be drawn between this picture of hybrid structure and that of baryons, in which diquark (quark+quark) correlations play a key role. The potential of this formulation is illustrated by calculating the spectrum of light-quark isovector hybrid mesons. |
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Address |
[Xu, Shu-Sheng] Nanjing Univ Posts & Telecommun, Sch Sci, Nanjing 210023, Jiangsu, Peoples R China, Email: leichang@nankai.edu.cn; |
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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 |
1434-6001 |
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:000476540800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4088 |
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