Pub Date : 2024-08-06DOI: 10.1088/1361-6471/ad66ee
Niseem Magdy and Roy Lacey
Employing the AMPT transport model, we investigate the response of the rapidity-even dipolar flow ( ) and its associated Global Momentum Conservation (GMC) parameter K to structural disparities within 96Ru and 96Zr nuclei. We analyze Ru + Ru and Zr + Zr collisions at a center-of-mass energy of = 200 GeV. Our analysis demonstrates that the eccentricity ε1, and K exhibit subtle yet discernible sensitivity to the input nuclear structure distinctions between 96Ru and 96Zr isobars. This observation suggests that measuring and the GMC parameter in these isobaric collisions could serve as a means to fine-tune the comprehension of their nuclear structure disparities and offer insights to enhance the initial condition assumptions of theoretical models.
{"title":"Exploring rapidity-even dipolar flow in isobaric collisions at RHIC","authors":"Niseem Magdy and Roy Lacey","doi":"10.1088/1361-6471/ad66ee","DOIUrl":"https://doi.org/10.1088/1361-6471/ad66ee","url":null,"abstract":"Employing the AMPT transport model, we investigate the response of the rapidity-even dipolar flow ( ) and its associated Global Momentum Conservation (GMC) parameter K to structural disparities within 96Ru and 96Zr nuclei. We analyze Ru + Ru and Zr + Zr collisions at a center-of-mass energy of = 200 GeV. Our analysis demonstrates that the eccentricity ε1, and K exhibit subtle yet discernible sensitivity to the input nuclear structure distinctions between 96Ru and 96Zr isobars. This observation suggests that measuring and the GMC parameter in these isobaric collisions could serve as a means to fine-tune the comprehension of their nuclear structure disparities and offer insights to enhance the initial condition assumptions of theoretical models.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"23 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-08-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141942463","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-25DOI: 10.1088/1361-6471/ad6170
Bhoomika Maheshwari and Kosuke Nomura
The work reports a novel application of the interacting boson model in light-mass region around 48Ca, that takes into account intruder states and configuration mixing. The model is shown to provide a reasonable description of the observed low-lying yrast and yrare states of the N = 28 even–even isotones from Si to Fe, and even–even Ca isotopes. The nature of states is addressed in terms of the competition between spherical and deformed intruder configurations, and the rigidity of the N = 28 shell gap is tested, particularly for 44S. The isomer in 44S is shown to arise from a weak mixing between the two configurations and called as shape isomer. The unresolved low-lying spectra in 46Ar is also approached using the core-excitations across N = 28 shell. The SU(3) structure in 42Si is supported by the present calculation. The nearly spherical nature of 50Ti, 52Cr, 54Fe and 42,44,46Ca isotopes is found, while the core excitations are found to be essential for the description of yrare states. Shell model calculation is also performed for comparison.
这项工作报告了相互作用玻色子模型在 48Ca 附近轻质量区域的新应用，其中考虑到了侵入态和构型混合。结果表明，该模型合理地描述了从硅到铁的 N = 28 偶偶同素异形体以及偶偶钙同素异形体中观测到的低洼镱态和镱态。从球形构型和变形侵入构型之间的竞争角度探讨了状态的性质，并检验了 N = 28 壳间隙的刚性，特别是 44S 的刚性。结果表明，44S 中的异构体产生于两种构型之间的微弱混合，被称为形状异构体。此外，还利用 N = 28 壳间的核跃迁研究了 46Ar 中未解析的低频光谱。本计算支持 42Si 中的 SU(3) 结构。发现了 50Ti、52Cr、54Fe 和 42、44、46Ca 同位素的近似球形性质，同时发现核激发对于描述稀态至关重要。为了进行比较，还进行了壳模型计算。
{"title":"Weakening of N = 28 shell gap and the nature of 02+ states","authors":"Bhoomika Maheshwari and Kosuke Nomura","doi":"10.1088/1361-6471/ad6170","DOIUrl":"https://doi.org/10.1088/1361-6471/ad6170","url":null,"abstract":"The work reports a novel application of the interacting boson model in light-mass region around 48Ca, that takes into account intruder states and configuration mixing. The model is shown to provide a reasonable description of the observed low-lying yrast and yrare states of the N = 28 even–even isotones from Si to Fe, and even–even Ca isotopes. The nature of states is addressed in terms of the competition between spherical and deformed intruder configurations, and the rigidity of the N = 28 shell gap is tested, particularly for 44S. The isomer in 44S is shown to arise from a weak mixing between the two configurations and called as shape isomer. The unresolved low-lying spectra in 46Ar is also approached using the core-excitations across N = 28 shell. The SU(3) structure in 42Si is supported by the present calculation. The nearly spherical nature of 50Ti, 52Cr, 54Fe and 42,44,46Ca isotopes is found, while the core excitations are found to be essential for the description of yrare states. Shell model calculation is also performed for comparison.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"61 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771379","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-23DOI: 10.1088/1361-6471/ad60e6
P Acharya, M Fritts, D-M Mei, G-J Wang, R Mahapatra and M Platt
This study explores the dynamics of charge transport within a cryogenic P-type Ge particle detector, fabricated from a crystal cultivated at the University of South Dakota. By subjecting the detector to cryogenic temperatures and an Am-241 source, we observe evolving charge dynamics and the emergence of cluster dipole states, leading to the impact ionization process at 40 mK. Our analysis focuses on crucial parameters: the zero-field cross-section of cluster dipole states and the binding energy of these states. For the Ge detector in our investigation, the zero-field cross-section of cluster dipole states is determined to be 8.45 × 10−11 ± 4.22 × 10−12 cm2. Examination of the binding energy associated with cluster dipole states, formed by charge trapping onto dipole states during the freeze-out process, reveals a value of 0.034 ± 0.0017 meV. These findings shed light on the intricate charge states influenced by the interplay of temperature and electric field, with potential implications for the sensitivity in detecting low-mass dark matter.
这项研究探索了低温 P 型 Ge 粒子探测器内的电荷传输动力学，该探测器是由南达科他大学培育的晶体制成的。通过将探测器置于低温和 Am-241 源下，我们观察到了电荷动态的演变和簇偶极子态的出现，从而导致了 40 mK 时的撞击电离过程。我们的分析侧重于关键参数：簇偶极子态的零场截面和这些态的结合能。对于我们研究中的 Ge 探测器，簇偶极子态的零场截面被确定为 8.45 × 10-11 ± 4.22 × 10-12 cm2。对冻结过程中电荷捕获到偶极子态上而形成的与簇偶极子态相关的结合能的研究显示，其值为 0.034 ± 0.0017 meV。这些发现揭示了受温度和电场相互作用影响的错综复杂的电荷态，对探测低质量暗物质的灵敏度具有潜在影响。
{"title":"Exploring charge transport dynamics in a cryogenic P-type germanium detector","authors":"P Acharya, M Fritts, D-M Mei, G-J Wang, R Mahapatra and M Platt","doi":"10.1088/1361-6471/ad60e6","DOIUrl":"https://doi.org/10.1088/1361-6471/ad60e6","url":null,"abstract":"This study explores the dynamics of charge transport within a cryogenic P-type Ge particle detector, fabricated from a crystal cultivated at the University of South Dakota. By subjecting the detector to cryogenic temperatures and an Am-241 source, we observe evolving charge dynamics and the emergence of cluster dipole states, leading to the impact ionization process at 40 mK. Our analysis focuses on crucial parameters: the zero-field cross-section of cluster dipole states and the binding energy of these states. For the Ge detector in our investigation, the zero-field cross-section of cluster dipole states is determined to be 8.45 × 10−11 ± 4.22 × 10−12 cm2. Examination of the binding energy associated with cluster dipole states, formed by charge trapping onto dipole states during the freeze-out process, reveals a value of 0.034 ± 0.0017 meV. These findings shed light on the intricate charge states influenced by the interplay of temperature and electric field, with potential implications for the sensitivity in detecting low-mass dark matter.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"80 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141771382","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-10DOI: 10.1088/1361-6471/ad5b79
Ashutosh Kumar Alok, Neetu Raj Singh Chundawat, Arindam Mandal and Bhavya Soni
In this work, we investigate the impact of neutrino decay in the presence of non-standard interactions (NSI) along with the effects of the Majorana phase on neutrino decay in matter in the context of two-flavor neutrino oscillations. These effects are studied on neutrino oscillation probabilities Pαβ ≡ P(να → νβ), and the difference for several accelerator and reactor neutrino experiments. We find that for Pαβ, the influence of the Majorana phase on decay in matter can be replicated by the simultaneous presence of both decay and NSI. However, precise measurements of the Pαβ and ΔPαβ observables have the potential to unequivocally identify the presence of the Majorana phase by discerning its effects from the concurrent presence of both decay and NSI.
{"title":"Majorana CP-violating phases and NSI effects in neutrino decay","authors":"Ashutosh Kumar Alok, Neetu Raj Singh Chundawat, Arindam Mandal and Bhavya Soni","doi":"10.1088/1361-6471/ad5b79","DOIUrl":"https://doi.org/10.1088/1361-6471/ad5b79","url":null,"abstract":"In this work, we investigate the impact of neutrino decay in the presence of non-standard interactions (NSI) along with the effects of the Majorana phase on neutrino decay in matter in the context of two-flavor neutrino oscillations. These effects are studied on neutrino oscillation probabilities Pαβ ≡ P(να → νβ), and the difference for several accelerator and reactor neutrino experiments. We find that for Pαβ, the influence of the Majorana phase on decay in matter can be replicated by the simultaneous presence of both decay and NSI. However, precise measurements of the Pαβ and ΔPαβ observables have the potential to unequivocally identify the presence of the Majorana phase by discerning its effects from the concurrent presence of both decay and NSI.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"44 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141614212","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-08DOI: 10.1088/1361-6471/ad59b9
László Gyulai, Gábor Bíró, Róbert Vértesi, Gergely Gábor Barnaföldi
We use open charm production to estimate how far we can see back in time in high-energy hadron-hadron collisions. We analyze the transverse momentum distributions of the identified D mesons from pp, p–Pb and A–A collisions at the ALICE and STAR experiments covering the energy range from sNN=200GeV up to 7 TeV. Within a non-extensive statistical framework, the common Tsallis parameters for D mesons represent higher temperature and more degrees of freedom than that of light-flavour hadrons. Assuming Bjorken-expansion, the production of D mesons corresponds to a significantly earlier proper time, τD = (0.18 ± 0.06)τLF.
我们利用开放粲子的产生来估算在高能强子-强子对撞中我们能看到多远的时间。我们分析了在 ALICE 和 STAR 实验中从 pp、p-Pb 和 A-A 对撞中发现的 D 介子的横动量分布，其能量范围从 sNN=200GeV 到 7 TeV。在非广延性统计框架内，D介子的普通Tsallis参数比轻味强子代表了更高的温度和更多的自由度。假设Bjorken膨胀，D介子的产生对应于一个明显更早的适当时间，τD = (0.18 ± 0.06)τLF 。
{"title":"How far can we see back in time in high-energy collisions using charm hadrons?","authors":"László Gyulai, Gábor Bíró, Róbert Vértesi, Gergely Gábor Barnaföldi","doi":"10.1088/1361-6471/ad59b9","DOIUrl":"https://doi.org/10.1088/1361-6471/ad59b9","url":null,"abstract":"We use open charm production to estimate how far we can see back in time in high-energy hadron-hadron collisions. We analyze the transverse momentum distributions of the identified D mesons from pp, p–Pb and A–A collisions at the ALICE and STAR experiments covering the energy range from <inline-formula>\u0000<tex-math>\u0000<?CDATA $sqrt{{s}_{mathrm{NN}}}=200,mathrm{GeV}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msqrt><mml:mrow><mml:msub><mml:mrow><mml:mi>s</mml:mi></mml:mrow><mml:mrow><mml:mi>NN</mml:mi></mml:mrow></mml:msub></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>200</mml:mn><mml:mspace width=\"0.25em\"></mml:mspace><mml:mi>GeV</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"jpgad59b9ieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> up to 7 TeV. Within a non-extensive statistical framework, the common Tsallis parameters for D mesons represent higher temperature and more degrees of freedom than that of light-flavour hadrons. Assuming Bjorken-expansion, the production of D mesons corresponds to a significantly earlier proper time, <italic toggle=\"yes\">τ</italic>\u0000<sub>D</sub> = (0.18 ± 0.06)<italic toggle=\"yes\">τ</italic>\u0000<sub>LF</sub>.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"78 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141567775","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-07-08DOI: 10.1088/1361-6471/ad59ba
Chong-Xing Yue, Xiao-Chen Sun, Na-Qian Zhang, Yang-Yang Bu
The singly charged <italic toggle="yes">SU</italic>(2)<sub> <italic toggle="yes">L</italic> </sub> singlet scalar is one of the very interesting new particles, as it can generate neutrino masses at loop level, produce contributions to various flavour observables. We study the possibility of detecting this kind of scalar predicted by the singly-charged scalar model at ILC via the lepton flavour violation process <inline-formula> <tex-math> <?CDATA ${e}^{+}{e}^{-}to {S}^{+}{S}^{-}to mu e+{/}!!!!{E}$?> </tex-math> <mml:math overflow="scroll"><mml:msup><mml:mrow><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mrow><mml:mi>S</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>S</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup><mml:mo>→</mml:mo><mml:mi>μ</mml:mi><mml:mi>e</mml:mi><mml:mo>+</mml:mo><mml:menclose notation="updiagonalstrike"><mml:mi>E</mml:mi></mml:menclose></mml:math> <inline-graphic xlink:href="jpgad59baieqn1.gif" xlink:type="simple"></inline-graphic> </inline-formula>. Considering the constraints on the free parameters, we obtain the expected sensitivities of the ILC with the center of mass energy <inline-formula> <tex-math> <?CDATA $sqrt{s}=1,mathrm{TeV}$?> </tex-math> <mml:math overflow="scroll"><mml:msqrt><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:mspace width="0.25em"></mml:mspace><mml:mi>TeV</mml:mi></mml:math> <inline-graphic xlink:href="jpgad59baieqn2.gif" xlink:type="simple"></inline-graphic> </inline-formula> and the integrated luminosity <inline-formula> <tex-math> <?CDATA ${ mathcal L }=$?> </tex-math> <mml:math overflow="scroll"><mml:mi mathvariant="script">L</mml:mi><mml:mo>=</mml:mo></mml:math> <inline-graphic xlink:href="jpgad59baieqn3.gif" xlink:type="simple"></inline-graphic> </inline-formula> 1.5 ab<sup>−1</sup> to the parameter space of the singly-charged scalar model. The prospective excluded mass range at 95% C.L. is <italic toggle="yes">M</italic> <sub> <italic toggle="yes">S</italic> </sub> ≳ 470 GeV, 410 GeV for the branching ratio <inline-formula> <tex-math> <?CDATA ${{ mathcal B }}_{mu e}$?> </tex-math> <mml:math overflow="scroll"><mml:msub><mml:mrow><mml:mi mathvariant="script">B</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi><mml:mi>e</mml:mi></mml:mrow></mml:msub></mml:math> <inline-graphic xlink:href="jpgad59baieqn4.gif" xlink:type="simple"></inline-graphic> </inline-formula> = 100% , 50%, respectively, while the scalar with <italic toggle="yes">M</italic> <sub> <italic toggle="yes">S</italic> </sub> ≳ 300 GeV is excluded at 95% C.L. for <inline-formula> <tex-math> <?CDATA ${{ mathcal B }}_{mu e}$?> </tex-math> <mml:math overflow="scroll"><mml:msub><mml:mrow><mml:mi mathvariant="script">B</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi
{"title":"Lepton flavour violation signal of the singly charged scalar singlet at the ILC","authors":"Chong-Xing Yue, Xiao-Chen Sun, Na-Qian Zhang, Yang-Yang Bu","doi":"10.1088/1361-6471/ad59ba","DOIUrl":"https://doi.org/10.1088/1361-6471/ad59ba","url":null,"abstract":"The singly charged <italic toggle=\"yes\">SU</italic>(2)<sub>\u0000<italic toggle=\"yes\">L</italic>\u0000</sub> singlet scalar is one of the very interesting new particles, as it can generate neutrino masses at loop level, produce contributions to various flavour observables. We study the possibility of detecting this kind of scalar predicted by the singly-charged scalar model at ILC via the lepton flavour violation process <inline-formula>\u0000<tex-math>\u0000<?CDATA ${e}^{+}{e}^{-}to {S}^{+}{S}^{-}to mu e+{/}!!!!{E}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msup><mml:mrow><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>e</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup><mml:mo>→</mml:mo><mml:msup><mml:mrow><mml:mi>S</mml:mi></mml:mrow><mml:mrow><mml:mo>+</mml:mo></mml:mrow></mml:msup><mml:msup><mml:mrow><mml:mi>S</mml:mi></mml:mrow><mml:mrow><mml:mo>−</mml:mo></mml:mrow></mml:msup><mml:mo>→</mml:mo><mml:mi>μ</mml:mi><mml:mi>e</mml:mi><mml:mo>+</mml:mo><mml:menclose notation=\"updiagonalstrike\"><mml:mi>E</mml:mi></mml:menclose></mml:math>\u0000<inline-graphic xlink:href=\"jpgad59baieqn1.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. Considering the constraints on the free parameters, we obtain the expected sensitivities of the ILC with the center of mass energy <inline-formula>\u0000<tex-math>\u0000<?CDATA $sqrt{s}=1,mathrm{TeV}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msqrt><mml:mrow><mml:mi>s</mml:mi></mml:mrow></mml:msqrt><mml:mo>=</mml:mo><mml:mn>1</mml:mn><mml:mspace width=\"0.25em\"></mml:mspace><mml:mi>TeV</mml:mi></mml:math>\u0000<inline-graphic xlink:href=\"jpgad59baieqn2.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> and the integrated luminosity <inline-formula>\u0000<tex-math>\u0000<?CDATA ${ mathcal L }=$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:mi mathvariant=\"script\">L</mml:mi><mml:mo>=</mml:mo></mml:math>\u0000<inline-graphic xlink:href=\"jpgad59baieqn3.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> 1.5 ab<sup>−1</sup> to the parameter space of the singly-charged scalar model. The prospective excluded mass range at 95% C.L. is <italic toggle=\"yes\">M</italic>\u0000<sub>\u0000<italic toggle=\"yes\">S</italic>\u0000</sub> ≳ 470 GeV, 410 GeV for the branching ratio <inline-formula>\u0000<tex-math>\u0000<?CDATA ${{ mathcal B }}_{mu e}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi mathvariant=\"script\">B</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi><mml:mi>e</mml:mi></mml:mrow></mml:msub></mml:math>\u0000<inline-graphic xlink:href=\"jpgad59baieqn4.gif\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> = 100% , 50%, respectively, while the scalar with <italic toggle=\"yes\">M</italic>\u0000<sub>\u0000<italic toggle=\"yes\">S</italic>\u0000</sub> ≳ 300 GeV is excluded at 95% C.L. for <inline-formula>\u0000<tex-math>\u0000<?CDATA ${{ mathcal B }}_{mu e}$?>\u0000</tex-math>\u0000<mml:math overflow=\"scroll\"><mml:msub><mml:mrow><mml:mi mathvariant=\"script\">B</mml:mi></mml:mrow><mml:mrow><mml:mi>μ</mml:mi","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"366 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-07-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141567774","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-30DOI: 10.1088/1361-6471/ad57d7
T R Routray, S Sahoo, X Viñas, D N Basu and M Centelles
The equation of state (EoS) of hot neutron star matter (NSM) of n+p+e+μ composition in β-equilibrium is studied for both neutrino-free isothermal and neutrino-trapped isoentropic conditions, using the formalism where the thermal evolution is built upon its zero-temperature predictions in a self-consistent manner. The accuracy of the parabolic approximation, often used in the finite temperature calculation of hot NSM, is verified by comparing with the results obtained from the exact evaluation in the neutrino-free NSM. The EoS of neutrino-trapped isoentropic matter at low entropic condition, relevant to the core-collapsing supernovae, is formulated. In the isoentropic matter, the particle fractions and EoS have marginal variance as entropy per particle vary between 1 and 3 (in the unit of kB), but the temperature profile shows marked variation. The isentropes are found to be much less sensitive to the nuclear matter incompressibility, but have large dependence on the slope parameter L. The bulk properties of the neutron stars predicted by the isoentropic EoSs for different entropy are calculated. A model calculation for the early stage evolution of protoneutron star to neutron star configuration is also given.
利用热演化以自洽方式建立在零温预测基础上的形式主义，研究了 n+p+e+μ 组成的热中子星物质（NSM）在 β 平衡条件下的状态方程（EoS），包括无中微子等温和中微子俘获等熵条件。抛物线近似常用于热NSM的有限温度计算，通过与无中微子NSM精确评估的结果进行比较，验证了抛物线近似的准确性。在低熵条件下，制定了中微子捕获的等熵物质的 EoS，这与内核坍缩超新星有关。在等熵物质中，由于每个粒子的熵在 1 到 3 之间变化（单位 kB），粒子分数和 EoS 具有边际差异，但温度曲线显示出明显的变化。我们发现等熵对核物质不可压缩性的敏感度要低得多，但对斜率参数 L 的依赖性很大。还给出了原中子星向中子星构型演化早期阶段的模型计算。
{"title":"Equation of state of hot neutron star matter using finite range simple effective interaction","authors":"T R Routray, S Sahoo, X Viñas, D N Basu and M Centelles","doi":"10.1088/1361-6471/ad57d7","DOIUrl":"https://doi.org/10.1088/1361-6471/ad57d7","url":null,"abstract":"The equation of state (EoS) of hot neutron star matter (NSM) of n+p+e+μ composition in β-equilibrium is studied for both neutrino-free isothermal and neutrino-trapped isoentropic conditions, using the formalism where the thermal evolution is built upon its zero-temperature predictions in a self-consistent manner. The accuracy of the parabolic approximation, often used in the finite temperature calculation of hot NSM, is verified by comparing with the results obtained from the exact evaluation in the neutrino-free NSM. The EoS of neutrino-trapped isoentropic matter at low entropic condition, relevant to the core-collapsing supernovae, is formulated. In the isoentropic matter, the particle fractions and EoS have marginal variance as entropy per particle vary between 1 and 3 (in the unit of kB), but the temperature profile shows marked variation. The isentropes are found to be much less sensitive to the nuclear matter incompressibility, but have large dependence on the slope parameter L. The bulk properties of the neutron stars predicted by the isoentropic EoSs for different entropy are calculated. A model calculation for the early stage evolution of protoneutron star to neutron star configuration is also given.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"35 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141509387","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-19DOI: 10.1088/1361-6471/ad5196
T J Gao, H D Wang, Jing-Bin Lu, Yi Lu, Pei-Yao Yang and M J Qin
A Bayesian neural network (BNN) is developed to predict the 1st excitation energy of odd–odd nuclei. Aside from the proton number and neutron number, we introduce two empirical physical quantities into the input layer. is introduced to distinguish even–even, odd–odd and odd-A nuclei; and the so-called Casten factor is introduced to stand for collectivity. The BNN is trained with an experimental dataset of the 1st excitation energy for 434 odd–odd, 649 even–even and 1050 odd-A nuclei. After training, the BNN predicts the 1st excitation energy of odd–odd nuclei with a rms of 0.21 MeV. Examples of Dy, Gd, Eu and Cs isotopes are also shown. The BNN results show moderate predictive ability, in comparison with results from the projected Hartree–Fock method.
{"title":"Prediction of the 1st excitation energy of odd–odd nuclei with the Bayesian neural network approach","authors":"T J Gao, H D Wang, Jing-Bin Lu, Yi Lu, Pei-Yao Yang and M J Qin","doi":"10.1088/1361-6471/ad5196","DOIUrl":"https://doi.org/10.1088/1361-6471/ad5196","url":null,"abstract":"A Bayesian neural network (BNN) is developed to predict the 1st excitation energy of odd–odd nuclei. Aside from the proton number and neutron number, we introduce two empirical physical quantities into the input layer. is introduced to distinguish even–even, odd–odd and odd-A nuclei; and the so-called Casten factor is introduced to stand for collectivity. The BNN is trained with an experimental dataset of the 1st excitation energy for 434 odd–odd, 649 even–even and 1050 odd-A nuclei. After training, the BNN predicts the 1st excitation energy of odd–odd nuclei with a rms of 0.21 MeV. Examples of Dy, Gd, Eu and Cs isotopes are also shown. The BNN results show moderate predictive ability, in comparison with results from the projected Hartree–Fock method.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"13 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516933","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-18DOI: 10.1088/1361-6471/ad4bf8
D Siegmann, F Edzards, C Bruch, M Biassoni, M Carminati, M Descher, C Fiorini, C Forstner, A Gavin, M Gugiatti, R Hiller, D Hinz, T Houdy, A Huber, P King, P Lechner, S Lichter, D Mießner, A Nava, A Onillon, D C Radford, D Spreng, M Steidl, P Trigilio, K Urban, D Vénos, J Wolfb and S Mertens
Sterile neutrinos in the keV mass range present a viable candidate for dark matter. They can be detected through single β -decay, where they cause small spectral distortions. The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to search for keV-scale sterile neutrinos with high sensitivity. To achieve this, the KATRIN beamline will be equipped with a novel multi-pixel silicon drift detector focal plane array named TRISTAN. In this study, we present the performance of a TRISTAN detector module, a component of the eventual 9-module system. Our investigation encompasses spectroscopic aspects such as noise performance, energy resolution, linearity, and stability.
{"title":"Development of a silicon drift detector array to search for keV-scale sterile neutrinos with the KATRIN experiment","authors":"D Siegmann, F Edzards, C Bruch, M Biassoni, M Carminati, M Descher, C Fiorini, C Forstner, A Gavin, M Gugiatti, R Hiller, D Hinz, T Houdy, A Huber, P King, P Lechner, S Lichter, D Mießner, A Nava, A Onillon, D C Radford, D Spreng, M Steidl, P Trigilio, K Urban, D Vénos, J Wolfb and S Mertens","doi":"10.1088/1361-6471/ad4bf8","DOIUrl":"https://doi.org/10.1088/1361-6471/ad4bf8","url":null,"abstract":"Sterile neutrinos in the keV mass range present a viable candidate for dark matter. They can be detected through single β -decay, where they cause small spectral distortions. The Karlsruhe Tritium Neutrino (KATRIN) experiment aims to search for keV-scale sterile neutrinos with high sensitivity. To achieve this, the KATRIN beamline will be equipped with a novel multi-pixel silicon drift detector focal plane array named TRISTAN. In this study, we present the performance of a TRISTAN detector module, a component of the eventual 9-module system. Our investigation encompasses spectroscopic aspects such as noise performance, energy resolution, linearity, and stability.","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"21 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516934","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-06-11DOI: 10.1088/1361-6471/ad4faa
José Nicolás Orce and Cebo Ngwetsheni
New equations for the electric dipole polarizability αE1 of low-lying excited states in atomic nuclei—and the related (−2) moment of the total photo-absorption cross section, σ−2—are inferred in terms of electric dipole and quadrupole matrix elements. These equations are valid for arbitrary angular momenta of the initial/ground and final/excited states and have been exploited in fully converged 1ℏω shell-model (SM) calculations of selected p- and sd-shell nuclei that consider configuration mixing; advancing previous knowledge from 17O to 36Ar, where thousands of electric dipole matrix elements are computed from isovector excitations which include the giant dipole resonance (GDR) region. Our results are in reasonable agreement with previous SM calculations and follow—except for 6,7Li and 17,18O—Migdal’s global trend provided by the combination of the hydrodynamic model and second-order non-degenerate perturbation theory. Discrepancies in 6,7Li and 17O arise as a result of the presence of α-cluster configurations in odd-mass nuclei, whereas the disagreement in 18O comes from the mixing of intruder states, which is lacking in the SM interactions. More advanced ab initio calculations of the dipole polarizability for low-lying excited states covering all the isovector states within the GDR region are missing and could be very valuable to benchmark the results presented here and shed further light on how atomic nuclei polarize away from the ground state
根据电偶极子和四极矩阵元素，推断出了原子核中低洼激发态的电偶极子极化率 αE1 的新方程，以及相关的总光吸收截面 (-2) 矩 σ-2。这些方程对初始态/基态和最终态/激发态的任意角矩都是有效的，并在考虑构型混合的选定 p 壳核和 sd 壳核的完全收敛 1ℏω 壳模型（SM）计算中得到了利用；推进了从 17O 到 36Ar 的先前知识，其中数千个电偶极子矩阵元素是通过包括巨偶极子共振（GDR）区域在内的等矢量激发计算得出的。我们的结果与之前的 SM 计算结果相当吻合，而且除了 6,7Li 和 17,18O 外，都遵循了米格达尔流体力学模型与二阶非退化扰动理论相结合所提供的全球趋势。6,7Li 和 17O 中的差异是由于奇数质量原子核中存在 α 簇构型，而 18O 中的差异则是由于入侵态的混合，这在 SM 相互作用中是缺乏的。对低洼激发态的偶极极化率进行的更先进的 Ab initio 计算涵盖了 GDR 区域内的所有等矢量态，但这种计算目前还很欠缺，因此对本文介绍的结果可能非常有价值，并能进一步揭示原子核如何偏离基态极化。
{"title":"Electric dipole polarizability of low-lying excited states in atomic nuclei","authors":"José Nicolás Orce and Cebo Ngwetsheni","doi":"10.1088/1361-6471/ad4faa","DOIUrl":"https://doi.org/10.1088/1361-6471/ad4faa","url":null,"abstract":"New equations for the electric dipole polarizability αE1 of low-lying excited states in atomic nuclei—and the related (−2) moment of the total photo-absorption cross section, σ−2—are inferred in terms of electric dipole and quadrupole matrix elements. These equations are valid for arbitrary angular momenta of the initial/ground and final/excited states and have been exploited in fully converged 1ℏω shell-model (SM) calculations of selected p- and sd-shell nuclei that consider configuration mixing; advancing previous knowledge from 17O to 36Ar, where thousands of electric dipole matrix elements are computed from isovector excitations which include the giant dipole resonance (GDR) region. Our results are in reasonable agreement with previous SM calculations and follow—except for 6,7Li and 17,18O—Migdal’s global trend provided by the combination of the hydrodynamic model and second-order non-degenerate perturbation theory. Discrepancies in 6,7Li and 17O arise as a result of the presence of α-cluster configurations in odd-mass nuclei, whereas the disagreement in 18O comes from the mixing of intruder states, which is lacking in the SM interactions. More advanced ab initio calculations of the dipole polarizability for low-lying excited states covering all the isovector states within the GDR region are missing and could be very valuable to benchmark the results presented here and shed further light on how atomic nuclei polarize away from the ground state","PeriodicalId":16766,"journal":{"name":"Journal of Physics G: Nuclear and Particle Physics","volume":"31 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141516935","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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