Decays of unstable heavy particles usually involve the coherent sum of several amplitudes, like in a multiple slit experiment. Dedicated amplitude analysis techniques have been widely used to resolve these amplitudes for better understanding of the underlying dynamics. In special cases where two spin-1/2 particles and two (pseudo-) scalar particles are present in the process, multiple equivalent solutions are found owing to intrinsic symmetries in the summed probability density function. In this study, the problem of multiple solutions is discussed, and a scheme to overcome this problem is proposed by fixing some free parameters. Toys are generated to validate the strategy. A new approach to align the helicities of initial- and final-state particles in different decay chains is also introduced.
{"title":"A scheme to fix multiple solutions in amplitude analyses* * Supported by the National Natural Science Foundation of China (NSFC) (12061141007, 12175005) and by the National Key R&D Program of China (2022YFA1601904)","authors":"Yuanning Gao, Tianze Rong, Zhenwei Yang, Chenjia Zhang, Yanxi Zhang","doi":"10.1088/1674-1137/ad2674","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2674","url":null,"abstract":"Decays of unstable heavy particles usually involve the coherent sum of several amplitudes, like in a multiple slit experiment. Dedicated amplitude analysis techniques have been widely used to resolve these amplitudes for better understanding of the underlying dynamics. In special cases where two spin-1/2 particles and two (pseudo-) scalar particles are present in the process, multiple equivalent solutions are found owing to intrinsic symmetries in the summed probability density function. In this study, the problem of multiple solutions is discussed, and a scheme to overcome this problem is proposed by fixing some free parameters. Toys are generated to validate the strategy. A new approach to align the helicities of initial- and final-state particles in different decay chains is also introduced.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140586816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-01DOI: 10.1088/1674-1137/ad2b56
Rui-Qin Wang, Ji-Peng Lv, Yan-Hao Li, Jun Song, Feng-Lan Shao
We study the production of light nuclei in the coalescence mechanism of Au-Au collisions at midrapidity at GeV. We derive analytic formulas of the momentum distributions of two bodies, three bodies, and four nucleons coalescing into light nuclei and naturally explain the transverse momentum spectra of the deuteron (d), triton (t), helium-3 (3He), and helium-4 (4He). We reproduce data on the yield rapidity densities, yield ratios, and averaged transverse momenta of d, t, 3He, and 4He and provide the proportions of contributions from different coalescence sources for t, 3He, and 4He in their production. We find that besides nucleon coalescence, nucleon+nucleus coalescence and nucleus+nucleus coalescence may play requisite roles in light nucleus production in Au-Au collisions at GeV.
{"title":"Different coalescence sources of light nucleus production in Au-Au collisions at GeV* * Supported in part by the National Natural Science Foundation of China (12175115,12375074), the Natural Science Foundation of Shandong Province, China (ZR2020MA097), and the Higher Educational Youth Innovation Science and Technology Program of Shandong Province, China (2020KJJ004, 2019KJJ010)","authors":"Rui-Qin Wang, Ji-Peng Lv, Yan-Hao Li, Jun Song, Feng-Lan Shao","doi":"10.1088/1674-1137/ad2b56","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2b56","url":null,"abstract":"We study the production of light nuclei in the coalescence mechanism of Au-Au collisions at midrapidity at <inline-formula>\u0000<tex-math><?CDATA $ sqrt{s_{NN}}=3 $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053112_M2.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>GeV. We derive analytic formulas of the momentum distributions of two bodies, three bodies, and four nucleons coalescing into light nuclei and naturally explain the transverse momentum spectra of the deuteron (<italic toggle=\"yes\">d</italic>), triton (<italic toggle=\"yes\">t</italic>), helium-3 (<sup>3</sup>He), and helium-4 (<sup>4</sup>He). We reproduce data on the yield rapidity densities, yield ratios, and averaged transverse momenta of <italic toggle=\"yes\">d</italic>, <italic toggle=\"yes\">t</italic>, <sup>3</sup>He, and <sup>4</sup>He and provide the proportions of contributions from different coalescence sources for <italic toggle=\"yes\">t</italic>, <sup>3</sup>He, and <sup>4</sup>He in their production. We find that besides nucleon coalescence, nucleon+nucleus coalescence and nucleus+nucleus coalescence may play requisite roles in light nucleus production in Au-Au collisions at <inline-formula>\u0000<tex-math><?CDATA $ sqrt{s_{NN}}=3 $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053112_M3.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> GeV.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805110","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-01DOI: 10.1088/1674-1137/ad2e83
Pan Li, Yi Ling
The Page curve plotted using the typical random state approximation is not applicable to a system with conserved quantities, such as the evaporation process of a charged black hole, during which the electric charge does not macroscopically radiate out with a uniform rate. In this context, the symmetry-resolved entanglement entropy may play a significant role in describing the entanglement structure of such a system. We attempt to impose constraints on microscopic quantum states to match the macroscopic phenomenon of charge radiation during black hole evaporation. Specifically, we consider a simple qubit system with conserved spin/charge serving as a toy model for the evaporation of charged black holes. We propose refined rules for selecting a random state with conserved quantities to simulate the distribution of charges during the different stages of evaporation and obtain refined Page curves that exhibit distinct features in contrast to the original Page curve. We find that the refined Page curve may have a different Page time and exhibit asymmetric behavior on both sides of the Page time. Such refined Page curves may provide a more realistic description for the entanglement between the charged black hole and radiation during the evaporation process.
{"title":"Refined symmetry-resolved Page curve and charged black holes* * Supported in part by the Natural Science Foundation of China (12035016, 12275275). It is also supported by the Beijing Natural Science Foundation (1222031) and the Innovative Projects of Science and Technology ( E2545BU210) at IHEP.","authors":"Pan Li, Yi Ling","doi":"10.1088/1674-1137/ad2e83","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2e83","url":null,"abstract":"The Page curve plotted using the typical random state approximation is not applicable to a system with conserved quantities, such as the evaporation process of a charged black hole, during which the electric charge does not macroscopically radiate out with a uniform rate. In this context, the symmetry-resolved entanglement entropy may play a significant role in describing the entanglement structure of such a system. We attempt to impose constraints on microscopic quantum states to match the macroscopic phenomenon of charge radiation during black hole evaporation. Specifically, we consider a simple qubit system with conserved spin/charge serving as a toy model for the evaporation of charged black holes. We propose refined rules for selecting a random state with conserved quantities to simulate the distribution of charges during the different stages of evaporation and obtain refined Page curves that exhibit distinct features in contrast to the original Page curve. We find that the refined Page curve may have a different Page time and exhibit asymmetric behavior on both sides of the Page time. Such refined Page curves may provide a more realistic description for the entanglement between the charged black hole and radiation during the evaporation process.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805023","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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}
The principle of maximum conformality (PMC) provides a systematic approach to solve the conventional renormalization scheme and scale ambiguities. Scale-fixed predictions of physical observables using the PMC are independent of the choice of renormalization scheme – a key requirement for renormalization group invariance. In this paper, we derive new degeneracy relations based on the renormalization group equations that involve both the usual β-function and the quark mass anomalous dimension -function. These new degeneracy relations enable improved PMC scale-setting procedures for correct magnitudes of the strong coupling constant and -running quark mass to be determined simultaneously. By using these improved PMC scale-setting procedures, the renormalization scale dependence of the -on-shell quark mass relation can be eliminated systematically. Consequently, the top-quark on-shell (or ) mass can be determined without conventional renormalization scale ambiguity. Taking the top-quark mass GeV as the input, we obtain GeV. Here, the uncertainties arise from errors combined with those from and the approximate uncertainty resulting from the uncalculated five-loop terms predicted through the Padé approximation approach.
{"title":"Precise determination of the top-quark on-shell mass via its scale- invariant perturbative relation to the top-quark mass * * Supported in part by the National Natural Science Foundation of China (12247129, 12175025, 12347101) and the Graduate Research and Innovation Foundation of Chongqing, China (ydstd1912)","authors":"Xu-Dong Huang, Xing-Gang Wu, Xu-Chang Zheng, Jiang Yan, Zhi-Fei Wu, Hong-Hao Ma","doi":"10.1088/1674-1137/ad2dbf","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2dbf","url":null,"abstract":"The principle of maximum conformality (PMC) provides a systematic approach to solve the conventional renormalization scheme and scale ambiguities. Scale-fixed predictions of physical observables using the PMC are independent of the choice of renormalization scheme – a key requirement for renormalization group invariance. In this paper, we derive new degeneracy relations based on the renormalization group equations that involve both the usual <italic toggle=\"yes\">β</italic>-function and the quark mass anomalous dimension <inline-formula>\u0000<tex-math><?CDATA $ gamma_m $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M4.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>-function. These new degeneracy relations enable improved PMC scale-setting procedures for correct magnitudes of the strong coupling constant and <inline-formula>\u0000<tex-math><?CDATA $ overline{{rm{MS}}} $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M5.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>-running quark mass to be determined simultaneously. By using these improved PMC scale-setting procedures, the renormalization scale dependence of the <inline-formula>\u0000<tex-math><?CDATA $ overline{{rm{MS}}} $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M6.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>-on-shell quark mass relation can be eliminated systematically. Consequently, the top-quark on-shell (or <inline-formula>\u0000<tex-math><?CDATA $ overline{{rm{MS}}} $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M7.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>) mass can be determined without conventional renormalization scale ambiguity. Taking the top-quark <inline-formula>\u0000<tex-math><?CDATA $ overline{{rm{MS}}} $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M8.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> mass <inline-formula>\u0000<tex-math><?CDATA $ {overline m}_t({overline m}_t)=162.5^{+2.1}_{-1.5} $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M9.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> GeV as the input, we obtain <inline-formula>\u0000<tex-math><?CDATA $ M_tsimeq 172.41^{+2.21}_{-1.57} $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M10.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> GeV. Here, the uncertainties arise from errors combined with those from <inline-formula>\u0000<tex-math><?CDATA $ Delta alpha_s(M_Z) $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053113_M11.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> and the approximate uncertainty resulting from the uncalculated five-loop terms predicted through the Padé approximation approach.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805051","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-01DOI: 10.1088/1674-1137/ad2b51
Lin Gao, Heping Ying, Jianbo Zhang
A modified deep convolutional generative adversarial network (M-DCGAN) frame is proposed to study the N-dimensional (ND) topological quantities in lattice QCD based on Monte Carlo (MC) simulations. We construct a new scaling structure including fully connected layers to support the generation of high-quality high-dimensional images for the M-DCGAN. Our results suggest that the M-DCGAN scheme of machine learning will help to more efficiently calculate the 1D distribution of topological charge and the 4D topological charge density compared with MC simulation alone.
我们提出了一种改进的深度卷积生成对抗网络（M-DCGAN）框架，用于研究基于蒙特卡洛（MC）模拟的网格 QCD 中的 N 维（ND）拓扑量。我们构建了一种新的缩放结构，包括全连接层，以支持 M-DCGAN 生成高质量的高维图像。我们的结果表明，与单独的 MC 模拟相比，机器学习的 M-DCGAN 方案将有助于更有效地计算拓扑电荷的一维分布和四维拓扑电荷密度。
{"title":"Study of the topological quantities of lattice QCD using a modified DCGAN frame","authors":"Lin Gao, Heping Ying, Jianbo Zhang","doi":"10.1088/1674-1137/ad2b51","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2b51","url":null,"abstract":"A modified deep convolutional generative adversarial network (M-DCGAN) frame is proposed to study the N-dimensional (ND) topological quantities in lattice QCD based on Monte Carlo (MC) simulations. We construct a new scaling structure including fully connected layers to support the generation of high-quality high-dimensional images for the M-DCGAN. Our results suggest that the M-DCGAN scheme of machine learning will help to more efficiently calculate the 1D distribution of topological charge and the 4D topological charge density compared with MC simulation alone.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805053","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-01DOI: 10.1088/1674-1137/ad2a4b
Junrong Wang, Ziwan Yu, Hong Mao
We investigate the dynamics of a first-order quark-hadron transition via homogeneous thermal nucleation in the two-flavor quark-meson model. The contribution of the fermionic vacuum loop in the effective thermodynamics potential and phase diagram, together with the location of the critical endpoint (CEP), is obtained in the temperature and chemical potential plane. For weak and strong first-order phase transitions, by taking the temperature as a variable, the critical bubble profiles, evolutions of the surface tension, and saddle-point action in the presence of a nucleation bubble are numerically calculated in detail when fixing the chemical potentials at and . Our results show that the system could be trapped in the metastable state for a long time as long as the temperature is between the metastable region characterized by the up and low spinodal lines. Moreover, the surface tension at criticality will rise to approximately when the chemical potential is very high. Such a small surface tension value would favor a mixed phase in the cores of compact stars and may have an important implication in astrophysics.
{"title":"Bubble nucleation in the two-flavor quark-meson model* * Supported in part by the National Natural Science Foundation of China (NSFC) (11675048)","authors":"Junrong Wang, Ziwan Yu, Hong Mao","doi":"10.1088/1674-1137/ad2a4b","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2a4b","url":null,"abstract":"We investigate the dynamics of a first-order quark-hadron transition via homogeneous thermal nucleation in the two-flavor quark-meson model. The contribution of the fermionic vacuum loop in the effective thermodynamics potential and phase diagram, together with the location of the critical endpoint (CEP), is obtained in the temperature and chemical potential plane. For weak and strong first-order phase transitions, by taking the temperature as a variable, the critical bubble profiles, evolutions of the surface tension, and saddle-point action in the presence of a nucleation bubble are numerically calculated in detail when fixing the chemical potentials at <inline-formula>\u0000<tex-math><?CDATA $mu=306~ mathrm{MeV}$?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053105_M1.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> and <inline-formula>\u0000<tex-math><?CDATA $mu=309 ~mathrm{MeV}$?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053105_M2.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula>. Our results show that the system could be trapped in the metastable state for a long time as long as the temperature is between the metastable region characterized by the up and low spinodal lines. Moreover, the surface tension at criticality will rise to approximately <inline-formula>\u0000<tex-math><?CDATA $4~ mathrm{MeV/fm^2}$?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053105_M3.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> when the chemical potential is very high. Such a small surface tension value would favor a mixed phase in the cores of compact stars and may have an important implication in astrophysics.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140586746","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-05-01DOI: 10.1088/1674-1137/ad24d1
Wei-Hao Han, Ye Xing, Ji Xu
Here, we study the production of charmonium pentaquarks from bottom baryon and B-meson decays under the flavor symmetry. Decay amplitudes for various processes are parameterized in terms of irreducible nonperturbative amplitudes. Numerous relations between decay widths are deduced. Moreover, the strong decays of pentaquarks are considered. Our results can be tested in future measurements at LHCb, Belle II, and CEPC. Once decay branching fractions are measured, this study will be useful for the exploration of new decay channels and pentaquark states.
在这里，我们研究了在味道对称条件下底重子和B-介子衰变产生的粲五夸克。各种过程的衰变振幅以不可还原的非微扰振幅为参数。推导出了衰变宽度之间的许多关系。此外，还考虑了五夸克的强衰变。我们的结果可以在 LHCb、Belle II 和 CEPC 的未来测量中得到检验。一旦测量到衰变分支分数，这项研究将有助于探索新的衰变通道和五夸克态。
{"title":"Production of charmonium pentaquarks from b-baryon and B-meson decays: SU(3) analysis* * W. H. H and J. X. is supported in part by the National Natural Science Foundation of China (12105247), the China Postdoctoral Science Foundation (2021M702957). Y.X is supported in part by the National Natural Science Foundation of China (12005294)","authors":"Wei-Hao Han, Ye Xing, Ji Xu","doi":"10.1088/1674-1137/ad24d1","DOIUrl":"https://doi.org/10.1088/1674-1137/ad24d1","url":null,"abstract":"Here, we study the production of charmonium pentaquarks <inline-formula>\u0000<tex-math><?CDATA $ c bar c q q q $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053106_M1.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> from bottom baryon and <italic toggle=\"yes\">B</italic>-meson decays under the flavor <inline-formula>\u0000<tex-math><?CDATA $S U(3) $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053106_Z-20240229104014.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> symmetry. Decay amplitudes for various processes are parameterized in terms of <inline-formula>\u0000<tex-math><?CDATA $S U(3) $?></tex-math>\u0000<inline-graphic xlink:href=\"cpc_48_5_053106_Z-20240229104040.jpg\" xlink:type=\"simple\"></inline-graphic>\u0000</inline-formula> irreducible nonperturbative amplitudes. Numerous relations between decay widths are deduced. Moreover, the strong decays of pentaquarks are considered. Our results can be tested in future measurements at LHCb, Belle II, and CEPC. Once decay branching fractions are measured, this study will be useful for the exploration of new decay channels and pentaquark states.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140586918","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-30DOI: 10.1088/1674-1137/ad2363
Jian-Hua Gao, 建华 高, Shi-Zheng Yang and 诗正 杨
We revisit the spin effects induced by thermal vorticity by calculating them directly from the spin-dependent distribution functions. For spin-1/2 particles, we provide the polarization up to the first order of thermal vorticity and compare it with the usual results calculated from the spin vector. For spin-1 particles, we show that all the non-diagonal elements vanish and there is no spin alignment up to the first order of thermal vortcity. We present the spin alignment at second-order contribution from thermal vorticity. We also show that the spin effects for both Dirac and vector particles receive an extra contribution when the spin direction is associated with the momentum of the particle.
{"title":"Revisiting the spin effects induced by thermal vorticity*","authors":"Jian-Hua Gao, 建华 高, Shi-Zheng Yang and 诗正 杨","doi":"10.1088/1674-1137/ad2363","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2363","url":null,"abstract":"We revisit the spin effects induced by thermal vorticity by calculating them directly from the spin-dependent distribution functions. For spin-1/2 particles, we provide the polarization up to the first order of thermal vorticity and compare it with the usual results calculated from the spin vector. For spin-1 particles, we show that all the non-diagonal elements vanish and there is no spin alignment up to the first order of thermal vortcity. We present the spin alignment at second-order contribution from thermal vorticity. We also show that the spin effects for both Dirac and vector particles receive an extra contribution when the spin direction is associated with the momentum of the particle.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805022","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-30DOI: 10.1088/1674-1137/ad2441
Tran Dzung Tri, Thanh Huy Nguyen and Khiem Hong Phan
We present one-loop contributions for with and in the extension of the standard model. In the phenomenological results, the signal strengths for at the Large Hadron Collider and for at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral models. We found that the contributions from the neutral gauge boson to the signal strengths are rather small. Consequently, the effects will be difficult to probe at future colliders. However, the impacts of charged Higgs and CP-odd Higgs in the chiral model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.
{"title":"One-loop contributions for and in the extension of the standard model*","authors":"Tran Dzung Tri, Thanh Huy Nguyen and Khiem Hong Phan","doi":"10.1088/1674-1137/ad2441","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2441","url":null,"abstract":"We present one-loop contributions for with and in the extension of the standard model. In the phenomenological results, the signal strengths for at the Large Hadron Collider and for at future lepton colliders are analyzed in the physical parameter space for both the vector and chiral models. We found that the contributions from the neutral gauge boson to the signal strengths are rather small. Consequently, the effects will be difficult to probe at future colliders. However, the impacts of charged Higgs and CP-odd Higgs in the chiral model on the signal strengths are significant and can be measured with the help of the initial polarization beams at future lepton colliders.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140805174","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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 : 2024-04-01DOI: 10.1088/1674-1137/ad2b4f
He-Xu Zhang, Shinya Matsuzaki, Hiroyuki Ishida
We discuss the gravitational wave (GW) spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors, which many flavor QCD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry breaking. We employ the linear-sigma model as the low-energy description of dark many flavor QCD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the (approximately realized) flat direction based on the Gildener-Weinberg mechanism. Passing through evaluation of the bubble nucleation/percolation, we address the reheating and relaxation processes, which are generically non-thermal and nonadiabatic. Parametrizing the reheating epoch in terms of the e-folding number, we propose proper formulae for the redshift effects on the GW frequencies and signal spectra. It then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz, unless the released latent heat is transported into another sector other than reheating the universe. Instead, models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity, like at LISA, BBO, and DECIGO, etc. We also find that with large flavors in the dark sector, the GW signals are made further smaller and the peak frequencies higher. Characteristic phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale, which is also briefly addressed.
{"title":"Gravitational wave footprints from Higgs-portal scalegenesis with multiple dark chiral scalars* * Supported in part by the National Science Foundation of China (NSFC) (11747308, 11975108, 12047569), the Seeds Funding of Jilin University (S.M.), and Toyama First Bank, Ltd (H.I.)","authors":"He-Xu Zhang, Shinya Matsuzaki, Hiroyuki Ishida","doi":"10.1088/1674-1137/ad2b4f","DOIUrl":"https://doi.org/10.1088/1674-1137/ad2b4f","url":null,"abstract":"We discuss the gravitational wave (GW) spectra predicted from the electroweak scalegenesis of the Higgs portal type with a large number of dark chiral flavors, which many flavor QCD would underlie and give the dynamical explanation of the negative Higgs portal coupling required to trigger the electroweak symmetry breaking. We employ the linear-sigma model as the low-energy description of dark many flavor QCD and show that the model undergoes ultra-supercooling due to the produced strong first-order thermal phase transition along the (approximately realized) flat direction based on the Gildener-Weinberg mechanism. Passing through evaluation of the bubble nucleation/percolation, we address the reheating and relaxation processes, which are generically non-thermal and nonadiabatic. Parametrizing the reheating epoch in terms of the e-folding number, we propose proper formulae for the redshift effects on the GW frequencies and signal spectra. It then turns out that the ultra-supercooling predicted from the Higgs-portal scalegenesis generically yields none of GW signals with the frequencies as low as nano Hz, unless the released latent heat is transported into another sector other than reheating the universe. Instead, models of this class prefer to give the higher frequency signals and still keeps the future prospected detection sensitivity, like at LISA, BBO, and DECIGO, etc. We also find that with large flavors in the dark sector, the GW signals are made further smaller and the peak frequencies higher. Characteristic phenomenological consequences related to the multiple chiral scalars include the prediction of dark pions with the mass much less than TeV scale, which is also briefly addressed.","PeriodicalId":10250,"journal":{"name":"Chinese Physics C","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"140316686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":2,"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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