The Asymptotic WGC has been proposed as a special case of the tower WGC that probes infinite distances in the moduli space corresponding to weakly coupled gauge regimes. The conjecture has been studied in M-theory on Calabi-Yau threefold (CY3) with finite volume inducing a 5D effective QFT. In this paper, we extend the scope of the previous study to encompass lower dimensions, particularly we generalise the obtained 5D asymptotic WGC to the effective field theory (EFT$_{3D}$) coupled to 3D gravity that descends from M-theory compactified on Calabi-Yau fourfold with an emphasis on $K3times K3$. We find that the CY4 has three fibration structures labelled as line Type-$mathbb {T}^{2}$, surface Type-$mathbb {S}$ and bulk Type-$mathbb {V}$. The emergent EFT$_{3D}$ is shown to have 2+2 towers of particles states termed as the BPS $mathcal {T}_{M_{mathrm{k}}rightarrow 0}^{rm{small {BPS}}}$ and $mathcal {T}_{M_{mathrm{k}}rightarrow infty }^{rm{small {BPS}}}$ as well as the non-BPS $mathcal {T}_{M_{mathrm{k}}rightarrow 0}^{rm{small {N-BPS}}}$ and $mathcal {T}_{M_{mathrm{k}}rightarrow infty }^{rm{small {N-BPS}}}$. To ensure the viability of the 3D Asymptotic WGC, we give explicit calculations to thoroughly test the swampland constraint for both the weakly and strongly gauge coupled regimes. Additional aspects, including the gauge symmetry breaking and duality symmetry are also investigated.
{"title":"Asymptotic Weak Gravity Conjecture in M-theory on K3 × K3","authors":"M Charkaoui, R Sammani, E H Saidi, R Ahl Laamara","doi":"10.1093/ptep/ptae100","DOIUrl":"https://doi.org/10.1093/ptep/ptae100","url":null,"abstract":"The Asymptotic WGC has been proposed as a special case of the tower WGC that probes infinite distances in the moduli space corresponding to weakly coupled gauge regimes. The conjecture has been studied in M-theory on Calabi-Yau threefold (CY3) with finite volume inducing a 5D effective QFT. In this paper, we extend the scope of the previous study to encompass lower dimensions, particularly we generalise the obtained 5D asymptotic WGC to the effective field theory (EFT$_{3D}$) coupled to 3D gravity that descends from M-theory compactified on Calabi-Yau fourfold with an emphasis on $K3times K3$. We find that the CY4 has three fibration structures labelled as line Type-$mathbb {T}^{2}$, surface Type-$mathbb {S}$ and bulk Type-$mathbb {V}$. The emergent EFT$_{3D}$ is shown to have 2+2 towers of particles states termed as the BPS $mathcal {T}_{M_{mathrm{k}}rightarrow 0}^{rm{small {BPS}}}$ and $mathcal {T}_{M_{mathrm{k}}rightarrow infty }^{rm{small {BPS}}}$ as well as the non-BPS $mathcal {T}_{M_{mathrm{k}}rightarrow 0}^{rm{small {N-BPS}}}$ and $mathcal {T}_{M_{mathrm{k}}rightarrow infty }^{rm{small {N-BPS}}}$. To ensure the viability of the 3D Asymptotic WGC, we give explicit calculations to thoroughly test the swampland constraint for both the weakly and strongly gauge coupled regimes. Additional aspects, including the gauge symmetry breaking and duality symmetry are also investigated.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"6 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500807","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
A closed string worldsheet of genus g with n punctures can be presented as a contact interaction in which n semi-infinite cylinders are glued together in a specific way via the Strebel differential on it, if n ≥ 1, 2g − 2 + n > 0. We construct a string field theory of closed strings such that all the Feynman diagrams are represented by such contact interactions. In order to do so, we define off-shell amplitudes in the underlying string theory using the combinatorial Fenchel-Nielsen coordinates to describe the moduli space and derive a recursion relation satisfied by them. Utilizing the Fokker-Planck formalism, we construct a string field theory from which the recursion relation can be deduced through the Schwinger-Dyson equation. The Fokker-Planck Hamiltonian consists of kinetic terms and three string interaction terms.
如果n≥1，2g - 2 + n > 0，则一个具有n个穿刺的g属封闭弦世界表可以呈现为一个接触相互作用，其中n个半无限圆柱体通过其上的斯特雷贝尔微分以特定方式粘合在一起。我们构建了一个封闭弦的弦场理论，使得所有费曼图都由这种接触相互作用表示。为此，我们在底层弦理论中定义了壳外振幅，使用组合芬切尔-尼尔森坐标来描述模空间，并推导出它们所满足的递推关系。利用福克-普朗克形式主义，我们构建了弦场论，并通过施温格-戴森方程推导出递归关系。福克-普朗克哈密顿由动力学项和三个弦相互作用项组成。
{"title":"Strebel differentials and string field theory","authors":"Nobuyuki Ishibashi","doi":"10.1093/ptep/ptae099","DOIUrl":"https://doi.org/10.1093/ptep/ptae099","url":null,"abstract":"A closed string worldsheet of genus g with n punctures can be presented as a contact interaction in which n semi-infinite cylinders are glued together in a specific way via the Strebel differential on it, if n ≥ 1, 2g − 2 + n > 0. We construct a string field theory of closed strings such that all the Feynman diagrams are represented by such contact interactions. In order to do so, we define off-shell amplitudes in the underlying string theory using the combinatorial Fenchel-Nielsen coordinates to describe the moduli space and derive a recursion relation satisfied by them. Utilizing the Fokker-Planck formalism, we construct a string field theory from which the recursion relation can be deduced through the Schwinger-Dyson equation. The Fokker-Planck Hamiltonian consists of kinetic terms and three string interaction terms.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"110 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500708","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
We consider an Einstein-Dirac-Maxwell system with two charged massless spinors coupled with an electromagnetic field, and construct a family of exact solutions to the system. The solution spacetime is an anisotropic generalization of the static Einstein universe which has a global cosmic magnetic field generated by the current of the spinors. The magnetic field is a force-free field that has played an important role in the study of cosmic magnetic fields. Our exact solution is regarded as a toy model which describes global cosmic magnetic phenomena in the early universe. The spinors are induced from Sasakian quasi-Killing spinors, and the total Dirac current flows along fibers of the Hopf-fibration. The magnetic field is a contact magnetic field.
{"title":"Anisotropic einstein universes with a global magetic field and SqK-spinors","authors":"Satsuki Matsuno, Fumihiro Ueno","doi":"10.1093/ptep/ptae098","DOIUrl":"https://doi.org/10.1093/ptep/ptae098","url":null,"abstract":"We consider an Einstein-Dirac-Maxwell system with two charged massless spinors coupled with an electromagnetic field, and construct a family of exact solutions to the system. The solution spacetime is an anisotropic generalization of the static Einstein universe which has a global cosmic magnetic field generated by the current of the spinors. The magnetic field is a force-free field that has played an important role in the study of cosmic magnetic fields. Our exact solution is regarded as a toy model which describes global cosmic magnetic phenomena in the early universe. The spinors are induced from Sasakian quasi-Killing spinors, and the total Dirac current flows along fibers of the Hopf-fibration. The magnetic field is a contact magnetic field.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"77 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500709","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Tahira Yasmeen, Ishtiaq Ahmed, Saba Shafaq, Muhammad Arslan, Muhammad Jamil Aslam
The experimental studies of the observables associated with the b → c transitions in the semileptonic B − meson decays at BaBar, Belle and LHCb have shown some deviations from the Standard Model (SM) predictions, consequently, providing a handy tool to probe the possible new physics (NP). In this context, we have first revisited the impact of recent measurements of R(D(*)) and R(Λc) on the parametric space of the NP scenarios. In addition, we have included the R(J/ψ) data in the analysis and found that their influence on the best-fit points and the parametric space is mild. Using the recent HFLAV data, after validating the well established sum rule of R(Λc), we derived the similar sum rule for R(J/ψ). Furthermore, according to the updated data, we have modified the correlation among the different observables, giving us their interesting interdependence. Finally, to discriminate the various NP scenarios, we have plotted the different angular observables and their ratios for B → D*τντ against the transfer momentum square (q2), using the 1σ and 2σ parametric space of considered NP scenarios. By implementing the collider bounds on NP Wilson coefficients, we find that, in the parametric space of some NP WCs is significantly restrained. To see the clear influence of NP on the amplitude of the angular observables, we have also calculated their numerical values in different q2 bins and shown them through the bar plots. We hope their precise measurements will help to discriminate various NP scenarios.
{"title":"Probing New Physics in light of recent developments in b → cℓν transitions","authors":"Tahira Yasmeen, Ishtiaq Ahmed, Saba Shafaq, Muhammad Arslan, Muhammad Jamil Aslam","doi":"10.1093/ptep/ptae086","DOIUrl":"https://doi.org/10.1093/ptep/ptae086","url":null,"abstract":"The experimental studies of the observables associated with the b → c transitions in the semileptonic B − meson decays at BaBar, Belle and LHCb have shown some deviations from the Standard Model (SM) predictions, consequently, providing a handy tool to probe the possible new physics (NP). In this context, we have first revisited the impact of recent measurements of R(D(*)) and R(Λc) on the parametric space of the NP scenarios. In addition, we have included the R(J/ψ) data in the analysis and found that their influence on the best-fit points and the parametric space is mild. Using the recent HFLAV data, after validating the well established sum rule of R(Λc), we derived the similar sum rule for R(J/ψ). Furthermore, according to the updated data, we have modified the correlation among the different observables, giving us their interesting interdependence. Finally, to discriminate the various NP scenarios, we have plotted the different angular observables and their ratios for B → D*τντ against the transfer momentum square (q2), using the 1σ and 2σ parametric space of considered NP scenarios. By implementing the collider bounds on NP Wilson coefficients, we find that, in the parametric space of some NP WCs is significantly restrained. To see the clear influence of NP on the amplitude of the angular observables, we have also calculated their numerical values in different q2 bins and shown them through the bar plots. We hope their precise measurements will help to discriminate various NP scenarios.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"35 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
We propose a minimal extended seesaw scheme based on the discrete symmetry A4 × Z4 × Z2 × Z8 which can successfully address neutrino phenomenology and keV sterile neutrino dark matter. The lepton mass hierarchy is naturally achieved. Active neutrino mixing angles can reached the best-fit points with the predictive Dirac CP violation phase. The active-sterile mixing matrix elements are small enough to access the observed cosmological dark matter abundance constraint with keV sterile neutrino dark matter. The effective neutrino masses are predicted to be in the ranges of the recent experimental limits.
{"title":"Neutrino phenomenology and keV dark matter in 2HDM with A4 symmetry","authors":"V V Vien","doi":"10.1093/ptep/ptae089","DOIUrl":"https://doi.org/10.1093/ptep/ptae089","url":null,"abstract":"We propose a minimal extended seesaw scheme based on the discrete symmetry A4 × Z4 × Z2 × Z8 which can successfully address neutrino phenomenology and keV sterile neutrino dark matter. The lepton mass hierarchy is naturally achieved. Active neutrino mixing angles can reached the best-fit points with the predictive Dirac CP violation phase. The active-sterile mixing matrix elements are small enough to access the observed cosmological dark matter abundance constraint with keV sterile neutrino dark matter. The effective neutrino masses are predicted to be in the ranges of the recent experimental limits.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"82 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
We discuss gravitational waves in an electroweakly interacting vector dark matter model. In the model, the electroweak gauge symmetry is extended to SU(2)0 × SU(2)1 × SU(2)2 × U(1)Y and spontaneously broken into SU(2)L × U(1)Y at TeV scale. The model has an exchange symmetry between SU(2)0 and SU(2)2. This symmetry stabilizes some massive vector bosons associated with the spontaneous symmetry breaking described above, and an electrically neutral one is a dark matter candidate. In the previous study, it was found that the gauge couplings of SU(2)0 and SU(2)1 are relatively large to explain the measured value of the dark matter energy density via the freeze-out mechanism. With the large gauge couplings, the gauge bosons potentially have a sizable effect on the scalar potential. In this paper, we focus on the phase transition of SU(2)0 × SU(2)1 × SU(2)2 → SU(2)L. We calculate the effective potential at finite temperature and find that the phase transition is first-order and strong in a wide range of the parameter space. The strong first-order phase transition generates gravitational waves. We calculate the gravitational wave spectrum and find that it is possible to detect the gravitational waves predicted in the model by future space-based gravitational wave interferometers. We explore the regions of the parameter space probed by the gravitational wave detection. We find that the gravitational wave detection can probe the region where the mass of h′, a CP-even scalar in the model, is a few TeV.
{"title":"Gravitational waves from first-order phase transition in an electroweakly interacting vector dark matter model","authors":"Tomohiro Abe, Katsuya Hashino","doi":"10.1093/ptep/ptae087","DOIUrl":"https://doi.org/10.1093/ptep/ptae087","url":null,"abstract":"We discuss gravitational waves in an electroweakly interacting vector dark matter model. In the model, the electroweak gauge symmetry is extended to SU(2)0 × SU(2)1 × SU(2)2 × U(1)Y and spontaneously broken into SU(2)L × U(1)Y at TeV scale. The model has an exchange symmetry between SU(2)0 and SU(2)2. This symmetry stabilizes some massive vector bosons associated with the spontaneous symmetry breaking described above, and an electrically neutral one is a dark matter candidate. In the previous study, it was found that the gauge couplings of SU(2)0 and SU(2)1 are relatively large to explain the measured value of the dark matter energy density via the freeze-out mechanism. With the large gauge couplings, the gauge bosons potentially have a sizable effect on the scalar potential. In this paper, we focus on the phase transition of SU(2)0 × SU(2)1 × SU(2)2 → SU(2)L. We calculate the effective potential at finite temperature and find that the phase transition is first-order and strong in a wide range of the parameter space. The strong first-order phase transition generates gravitational waves. We calculate the gravitational wave spectrum and find that it is possible to detect the gravitational waves predicted in the model by future space-based gravitational wave interferometers. We explore the regions of the parameter space probed by the gravitational wave detection. We find that the gravitational wave detection can probe the region where the mass of h′, a CP-even scalar in the model, is a few TeV.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"1 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-06-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141500710","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Saadi Ishaq, Sajawal Zafar, Abdur Rehman, Ishtiaq Ahmed
Motivated by the study of heavy-light meson production within the framework of heavy quark effective theory (HQET) factorization, we extend the factorization formalism for rather a complicated process W+ → B+ℓ+ℓ− in the limit of non-zero invariant squared-mass of dilepton, q2, at the lowest order in 1/mb up to $mathcal {O}(alpha _s)$. The purpose of the current study is to extend the HQET factorization formula for the W+ → B+ℓ+ℓ− process and subsequently compute the form factors for this channel up to next-to-leading order (NLO) corrections in αs. We explicitly show the amplitude of the W+ → B+ℓ+ℓ− process can also be factorized into a convolution between the perturbatively calculable hard-scattering kernel and the non-perturbative yet universal light-cone distribution amplitude (LCDA) defined in HQET. The validity of HQET factorization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. Within the HQET framework, we evaluate the form factors associated with the W+ → B+ℓ+ℓ− process, providing insights into its phenomenology. In addition, we also perform an exploratory phenomenological study on W+ → B+ℓ+ℓ− by employing an exponential model for the LCDAs for B+ meson. Our findings reveal that the branching ratio for W+ → B+ℓ+ℓ− is below 10−10. Although the branching ratios are small, this channel in high luminosity LHC experiments may serve to further constraints the value of λB.
{"title":"Semi-leptonic W decay to B meson with lepton pairs in HQET factorization upto O","authors":"Saadi Ishaq, Sajawal Zafar, Abdur Rehman, Ishtiaq Ahmed","doi":"10.1093/ptep/ptae080","DOIUrl":"https://doi.org/10.1093/ptep/ptae080","url":null,"abstract":"Motivated by the study of heavy-light meson production within the framework of heavy quark effective theory (HQET) factorization, we extend the factorization formalism for rather a complicated process W+ → B+ℓ+ℓ− in the limit of non-zero invariant squared-mass of dilepton, q2, at the lowest order in 1/mb up to $mathcal {O}(alpha _s)$. The purpose of the current study is to extend the HQET factorization formula for the W+ → B+ℓ+ℓ− process and subsequently compute the form factors for this channel up to next-to-leading order (NLO) corrections in αs. We explicitly show the amplitude of the W+ → B+ℓ+ℓ− process can also be factorized into a convolution between the perturbatively calculable hard-scattering kernel and the non-perturbative yet universal light-cone distribution amplitude (LCDA) defined in HQET. The validity of HQET factorization depends on the assumed scale hierarchy mW ∼ mb ≫ ΛQCD. Within the HQET framework, we evaluate the form factors associated with the W+ → B+ℓ+ℓ− process, providing insights into its phenomenology. In addition, we also perform an exploratory phenomenological study on W+ → B+ℓ+ℓ− by employing an exponential model for the LCDAs for B+ meson. Our findings reveal that the branching ratio for W+ → B+ℓ+ℓ− is below 10−10. Although the branching ratios are small, this channel in high luminosity LHC experiments may serve to further constraints the value of λB.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"40 7 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-05-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189697","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
We investigate the collective mode of a self-gravitating Bose-Einstein condensate (BEC) described by the Gross-Pitaevskii-Poisson (GPP) equations. The self-gravitating BEC has garnered considerable attention in cosmology and astrophysics, being proposed as a plausible candidate for dark matter. Our inquiry delves into the breathing and anisotropic collective modes by numerically solving the GPP equations and using the variational method. The breathing mode demonstrates a reduction in period with increasing total mass due to the density dependence of the self-gravitating BEC, attributed to the density-dependent nature of self-gravitating BECs, aligning quantitatively with our analytical findings. Additionally, we investigate an anisotropic collective mode in which the quadrupole mode intertwines with the breathing mode. The period of the quadrupole mode exhibits similar total mass dependence to that of the breathing mode. The characteristics of these periods differ from those of a conventional BEC confined by an external potential. Despite the differences in density dependence, the ratio of their periods equals that of the BEC confined by an isotropic harmonic potential. Furthermore, an extension of the variational method to a spheroidal configuration enables the isolation of solely the quadrupole mode from the anisotropic collective mode.
{"title":"Collective excitations of self-gravitating bose-einstein condensates: Breathing mode and appearance of anisotropy under self-gravity","authors":"Kenta Asakawa, Hideki Ishihara, Makoto Tsubota","doi":"10.1093/ptep/ptae078","DOIUrl":"https://doi.org/10.1093/ptep/ptae078","url":null,"abstract":"We investigate the collective mode of a self-gravitating Bose-Einstein condensate (BEC) described by the Gross-Pitaevskii-Poisson (GPP) equations. The self-gravitating BEC has garnered considerable attention in cosmology and astrophysics, being proposed as a plausible candidate for dark matter. Our inquiry delves into the breathing and anisotropic collective modes by numerically solving the GPP equations and using the variational method. The breathing mode demonstrates a reduction in period with increasing total mass due to the density dependence of the self-gravitating BEC, attributed to the density-dependent nature of self-gravitating BECs, aligning quantitatively with our analytical findings. Additionally, we investigate an anisotropic collective mode in which the quadrupole mode intertwines with the breathing mode. The period of the quadrupole mode exhibits similar total mass dependence to that of the breathing mode. The characteristics of these periods differ from those of a conventional BEC confined by an external potential. Despite the differences in density dependence, the ratio of their periods equals that of the BEC confined by an isotropic harmonic potential. Furthermore, an extension of the variational method to a spheroidal configuration enables the isolation of solely the quadrupole mode from the anisotropic collective mode.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"6 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141189779","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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}
Pairing correlations play an important role in a variety of nuclear phenomena. However, a quantitative understanding of proton–neutron (pn) pairing, especially isoscalar pn pairing (S = 1, T = 0) remains elusive. To clarify the property of pn pairing, we investigate the roles of pn pairing in the M1 transition of N = Z odd–odd nuclei. We develop a theoretical model based on the generator coordinate method (GCM) in which the isoscalar and isovector pn-pair amplitudes are used as the generator coordinates. Using the particle and the angular-momentum projections, the pn-pair GCM well reproduces the M1 transition of odd–odd nuclei for the exactly solvable SO(8) model. We apply the method to N = Z odd–odd nuclei and find that the experimental values of B(M1) are well reproduced. We also study the sensitivity of B(M1) to the strength of the isoscalar pairing interaction.
配对相关性在各种核现象中发挥着重要作用。然而，对质子-中子（pn）配对，尤其是等标pn配对（S = 1，T = 0）的定量理解仍然是个未知数。为了澄清 pn 配对的特性，我们研究了 pn 配对在 N = Z 奇多核的 M1 转变中的作用。我们建立了一个基于生成器坐标法（GCM）的理论模型，其中使用等视角和等矢量 pn 对振幅作为生成器坐标。利用粒子和角动量投影，pn 对 GCM 很好地再现了可精确求解的 SO(8) 模型中奇-偶核的 M1 转变。我们将该方法应用于 N = Z 奇-多原子核，发现 B(M1)的实验值得到了很好的再现。我们还研究了 B(M1)对等离子配对相互作用强度的敏感性。
{"title":"Generator coordinate method with proton–neutron pairing fluctuations and magnetic properties of N = Z odd–odd nuclei","authors":"K Uzawa, N Hinohara, T Nakatsukasa","doi":"10.1093/ptep/ptae072","DOIUrl":"https://doi.org/10.1093/ptep/ptae072","url":null,"abstract":"Pairing correlations play an important role in a variety of nuclear phenomena. However, a quantitative understanding of proton–neutron (pn) pairing, especially isoscalar pn pairing (S = 1, T = 0) remains elusive. To clarify the property of pn pairing, we investigate the roles of pn pairing in the M1 transition of N = Z odd–odd nuclei. We develop a theoretical model based on the generator coordinate method (GCM) in which the isoscalar and isovector pn-pair amplitudes are used as the generator coordinates. Using the particle and the angular-momentum projections, the pn-pair GCM well reproduces the M1 transition of odd–odd nuclei for the exactly solvable SO(8) model. We apply the method to N = Z odd–odd nuclei and find that the experimental values of B(M1) are well reproduced. We also study the sensitivity of B(M1) to the strength of the isoscalar pairing interaction.","PeriodicalId":20710,"journal":{"name":"Progress of Theoretical and Experimental Physics","volume":"26 1","pages":""},"PeriodicalIF":3.5,"publicationDate":"2024-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141059751","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"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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