WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)最新文献

{"title":"Reliability of QRPA approach to ββ and β decays","authors":"J. Terasaki, Y. Iwata","doi":"10.1063/1.5130988","DOIUrl":"https://doi.org/10.1063/1.5130988","url":null,"abstract":"We investigate the reliability of the quasiparticle random-phase approximation (QRPA) in application to the nuclear matrix element (NME) of the double-β decay of 136Xe. We examine the dependence of the NME of the two-neutrino double-β (2νββ) decay on the choice of the set of the intermediate-state energies, spectrum of the intermediate nucleus, the Gamow-Teller (GT) strength distribution, the GT strengths of the β decays of a nearby nucleus, and a higher-order term of the 2νββ NME recently proposed. The QRPA approach is a good approximation to the decay instance of 136Xe → 136Ba.We investigate the reliability of the quasiparticle random-phase approximation (QRPA) in application to the nuclear matrix element (NME) of the double-β decay of 136Xe. We examine the dependence of the NME of the two-neutrino double-β (2νββ) decay on the choice of the set of the intermediate-state energies, spectrum of the intermediate nucleus, the Gamow-Teller (GT) strength distribution, the GT strengths of the β decays of a nearby nucleus, and a higher-order term of the 2νββ NME recently proposed. The QRPA approach is a good approximation to the decay instance of 136Xe → 136Ba.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"82 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79311273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"On the generation of Majorana neutrino mass via quark condensate","authors":"A. Babič, S. Kovalenko, M. Krivoruchenko, F. Šimkovic","doi":"10.1063/1.5130962","DOIUrl":"https://doi.org/10.1063/1.5130962","url":null,"abstract":"We study a possibility of generation of the neutrino masses by a quark condensate resulting from a spontaneous break-down of the chiral symmetry. The existence of exotic scalar interactions between Majorana neutrinos and quarks in vacuum as well as in nuclear medium gives rise to a Majorana mass matrix. We construct the Majorana mass matrix and set limits on coupling constants of the exotic scalar interactions based on experiments searching for the neutrinoless double-beta decay.We study a possibility of generation of the neutrino masses by a quark condensate resulting from a spontaneous break-down of the chiral symmetry. The existence of exotic scalar interactions between Majorana neutrinos and quarks in vacuum as well as in nuclear medium gives rise to a Majorana mass matrix. We construct the Majorana mass matrix and set limits on coupling constants of the exotic scalar interactions based on experiments searching for the neutrinoless double-beta decay.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"2 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"89450746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New limit on two neutrino electron capture with positron emission in 106Cd","authors":"O. Polischuk, P. Belli, R. Bernabei, V. Brudanin, F. Cappella, V. Caracciolo, R. Cerulli, F. Danevich, A. Incicchitti, D. Kasperovych, V. Kobychev, V. Tretyak, M. Zarytskyy","doi":"10.1063/1.5130981","DOIUrl":"https://doi.org/10.1063/1.5130981","url":null,"abstract":"An experiment to search for double beta processes in 106Cd is in progress with the help of 106CdWO4 crystal scintillator (enriched in 106Cd to 66%) in coincidence with two large volume CdWO4 crystal scintillators in close geometry at the Gran Sasso Underground Laboratory. The time resolution of the set-up was analyzed, and the methods of pulse-shape discrimination of α and γ(β) events was applied to estimate the radioactive contamination of the crystal and to reduce the background counting rate. The possible double beta decay processes and the background components have been simulated by a Monte Carlo method with GEANT4. The experimental sensitivity is approaching the theoretical predictions for the two-neutrino electron capture with positron emission in 106Cd: lim T1/2≥4×1021 yr at 90% C.L. (the best previous limit was established in the previous stage of the experiment as T1/2≥1.1× 1021 yr, while the theoretical predictions are in the region of T1/2∼1021−1022 yr).An experiment to search for double beta processes in 106Cd is in progress with the help of 106CdWO4 crystal scintillator (enriched in 106Cd to 66%) in coincidence with two large volume CdWO4 crystal scintillators in close geometry at the Gran Sasso Underground Laboratory. The time resolution of the set-up was analyzed, and the methods of pulse-shape discrimination of α and γ(β) events was applied to estimate the radioactive contamination of the crystal and to reduce the background counting rate. The possible double beta decay processes and the background components have been simulated by a Monte Carlo method with GEANT4. The experimental sensitivity is approaching the theoretical predictions for the two-neutrino electron capture with positron emission in 106Cd: lim T1/2≥4×1021 yr at 90% C.L. (the best previous limit was established in the previous stage of the experiment as T1/2≥1.1× 1021 yr, while the theoretical predictions are in the region of T1/2∼1021−1022 yr).","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"91368800","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Lepton flavor violation processes in nuclei","authors":"O. Civitarese, T. Tarutina","doi":"10.1063/1.5130965","DOIUrl":"https://doi.org/10.1063/1.5130965","url":null,"abstract":"Lepton-flavor violation (LFV) processes in the presence of nuclei are revisited. The theoretical framework is constructed by considering a general Lagrangian written at quark level. By successive approximations the Lagrangian is converted into an effective one where the quark degrees of freedom are replaced by their nucleonic counterparts. The effective current operators are explicitly separated into spin dependent and spin independent terms. We focus, particularly, in the estimative of non-coherent processes. The case of (µ− → e−) LFV in 208Pb is given as an example about the use of the formalism.Lepton-flavor violation (LFV) processes in the presence of nuclei are revisited. The theoretical framework is constructed by considering a general Lagrangian written at quark level. By successive approximations the Lagrangian is converted into an effective one where the quark degrees of freedom are replaced by their nucleonic counterparts. The effective current operators are explicitly separated into spin dependent and spin independent terms. We focus, particularly, in the estimative of non-coherent processes. The case of (µ− → e−) LFV in 208Pb is given as an example about the use of the formalism.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"8 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86504911","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Efficient QRPA calculation for two-neutrino double-beta decay nuclear matrix element","authors":"N. Hinohara","doi":"10.1063/1.5130971","DOIUrl":"https://doi.org/10.1063/1.5130971","url":null,"abstract":"A formulation for calculating the double Gamow-Teller transition and two-neutrino double-beta decay nuclear matrix elements based on the linear response for nuclear density functional theory is presented. The matrix elements are expressed as double contour integration in the complex-energy plane. Test calculations for 48Ca double Gamow-Teller transition and 2νββ decay are performed in order to show the feasibility of this new approach.A formulation for calculating the double Gamow-Teller transition and two-neutrino double-beta decay nuclear matrix elements based on the linear response for nuclear density functional theory is presented. The matrix elements are expressed as double contour integration in the complex-energy plane. Test calculations for 48Ca double Gamow-Teller transition and 2νββ decay are performed in order to show the feasibility of this new approach.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"5 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75381635","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Preface: Workshop on Calculation of Double-Beta-Decay Matrix Elements (MEDEX’19)","authors":"CivitareseOsvaldo, SteklIvan, SuhonenJouni","doi":"10.1063/1.5130961","DOIUrl":"https://doi.org/10.1063/1.5130961","url":null,"abstract":"","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"17 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88926310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Nuclear responses for double beta decay and muon capture","authors":"L. Jokiniemi, J. Suhonen, H. Ejiri","doi":"10.1063/1.5130974","DOIUrl":"https://doi.org/10.1063/1.5130974","url":null,"abstract":"The existence of the neutrinoless double beta (0νββ) decay is one of the most intriguing open questions in the neutrino physics field. Despite many large-scale experiments have aimed to measure the reaction for decades, it has not yet been observed. Therefore, accurate theoretical calculations on 0νββ are crucial. To describe the double beta decay processes reliably one needs a possibility to test the involved virtual transitions against experimental data. In this work we manifest how to utilise the charge-exchange and ordinary muon capture (OMC) data in the study of 0νββ decay.The existence of the neutrinoless double beta (0νββ) decay is one of the most intriguing open questions in the neutrino physics field. Despite many large-scale experiments have aimed to measure the reaction for decades, it has not yet been observed. Therefore, accurate theoretical calculations on 0νββ are crucial. To describe the double beta decay processes reliably one needs a possibility to test the involved virtual transitions against experimental data. In this work we manifest how to utilise the charge-exchange and ordinary muon capture (OMC) data in the study of 0νββ decay.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"39 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85029643","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Study of double-β decay of 150Nd to the first 0+ excited level of 150Sm","authors":"D. Kasperovych, A. Barabash, P. Belli, R. Bernabei, R. Boiko, F. Cappella, V. Caracciolo, R. Cerulli, F. Danevich, A. Marco, A. Incicchitti, V. Kobychev, S. Konovalov, M. Laubenstein, D. Poda, O. Polischuk, V. Tretyak, V. Umatov","doi":"10.1063/1.5130975","DOIUrl":"https://doi.org/10.1063/1.5130975","url":null,"abstract":"Two-neutrino 2β decay of 150Nd to the 01+ 740.5-keV excited level of 150Sm has been investigated by using a highly purified 2.381-kg Nd2O3 sample with the help of ultra-low-background gamma spectrometer with 4 HPGe detectors (≈ 255 cm3 each) at the Gran Sasso underground laboratory (INFN, Italy). Gamma quanta, expected in cascade after de-excitation of the 01+ (740.5 keV) excited level of 150Sm, have been observed in the coincidence spectra accumulated over 25947 h. The half-life value has been preliminary estimated as T1/2=[ 6.9−1.9+4.0(stat)±1.1(syst) ]×109y. The data taking is in progress to reduce the statistical error.Two-neutrino 2β decay of 150Nd to the 01+ 740.5-keV excited level of 150Sm has been investigated by using a highly purified 2.381-kg Nd2O3 sample with the help of ultra-low-background gamma spectrometer with 4 HPGe detectors (≈ 255 cm3 each) at the Gran Sasso underground laboratory (INFN, Italy). Gamma quanta, expected in cascade after de-excitation of the 01+ (740.5 keV) excited level of 150Sm, have been observed in the coincidence spectra accumulated over 25947 h. The half-life value has been preliminary estimated as T1/2=[ 6.9−1.9+4.0(stat)±1.1(syst) ]×109y. The data taking is in progress to reduce the statistical error.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"33 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80609285","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Exotic neutrinoless double beta decay with Majoron-like emission","authors":"F. Deppisch","doi":"10.1063/1.5130967","DOIUrl":"https://doi.org/10.1063/1.5130967","url":null,"abstract":"We discuss a novel mode of neutrinoless double-β decay with emission of a light Majoron-like scalar particle ϕ which couples via an effective 7-dimensional operator with a (V + A) lepton current and (V ± A) quark currents leading to a long-range contribution. Future double-β decay searches are sensitive to scales of the order ΛNP ≈ 1 TeV for the effective operator. In a left-right symmetric model, this mode can probe right-handed W boson masses up to 25 TeV.We discuss a novel mode of neutrinoless double-β decay with emission of a light Majoron-like scalar particle ϕ which couples via an effective 7-dimensional operator with a (V + A) lepton current and (V ± A) quark currents leading to a long-range contribution. Future double-β decay searches are sensitive to scales of the order ΛNP ≈ 1 TeV for the effective operator. In a left-right symmetric model, this mode can probe right-handed W boson masses up to 25 TeV.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"104 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"80566088","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Two comments on double beta decay beyond the mass mechanism","authors":"M. Hirsch","doi":"10.1063/1.5130972","DOIUrl":"https://doi.org/10.1063/1.5130972","url":null,"abstract":"Neutrinoless double beta decay is usually discussed in connection with Majorana neutrino masses. However, it is well-known that many different contributions to the decay amplitude could in principle exist. In this talk, I will concentrate on two recent papers on such exotic contributions to 0νββ decay. First the uncertainty in the determination of the short-range (SR) coefficients due to the running of the SR operators at low energies, i.e. (0.1 − 1) GeV, will be discussed. Then, I will turn - once more - to the long-range (LR) part amplitude of 0νββ decay. Here, I discuss the decomposition of all d = 7 ΔL = 2 operators that contribute to LR 0νββ decay. d = 7 operators can lead to models that generate neutrino masses at tree-, 1-loop or 2-loop level. I show one example of a 2-loop model in which the LR amplitude completely dominates over the mass mechanism.Neutrinoless double beta decay is usually discussed in connection with Majorana neutrino masses. However, it is well-known that many different contributions to the decay amplitude could in principle exist. In this talk, I will concentrate on two recent papers on such exotic contributions to 0νββ decay. First the uncertainty in the determination of the short-range (SR) coefficients due to the running of the SR operators at low energies, i.e. (0.1 − 1) GeV, will be discussed. Then, I will turn - once more - to the long-range (LR) part amplitude of 0νββ decay. Here, I discuss the decomposition of all d = 7 ΔL = 2 operators that contribute to LR 0νββ decay. d = 7 operators can lead to models that generate neutrino masses at tree-, 1-loop or 2-loop level. I show one example of a 2-loop model in which the LR amplitude completely dominates over the mass mechanism.","PeriodicalId":23715,"journal":{"name":"WORKSHOP ON CALCULATION OF DOUBLE-BETA-DECAY MATRIX ELEMENTS (MEDEX’19)","volume":"1 1","pages":""},"PeriodicalIF":0.0,"publicationDate":"2019-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"85422714","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}