We present here a two-step method of classification and calculation for decay rates in the Standard Model. The first step is a phenomenological classification method, which is an extended and improved schematic experi...We present here a two-step method of classification and calculation for decay rates in the Standard Model. The first step is a phenomenological classification method, which is an extended and improved schematic experimental formula for decay width originally introduced by Chang. This schematic formula separates decays into seven classes. Furthermore, from it is derived a process-specific interaction energy m<sub>X</sub>. The second step is a numerical calculation method, which calculates this interaction energy m<sub>X</sub> numerically by minimization of action from the Lagrangian of the process, from which follows the decay width via the phenomenological formula. The Lagrangian is based on an extension of the Standard Model, the extended SU(4)-preon-model. A comparison of numerically calculated and observed decay widths for a large selection of decays shows a good agreement.展开更多
The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)si...The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)simulations with the ion extraction process in a laser-induced plasma as the major research background.Based on the theoretical analyses,the transport process of the charged particles including electrons and ions can be divided into three stages:electron oscillation and ion matrix sheath extraction stage,sheath expansion and ion rarefaction wave propagation stage and the plasma collapse stage,and the corresponding criterion for each stage is also presented.Consequently,a complete analytical model is established for describing the ion extraction flux at each stage during the decaying of the laser-induced plasmas under an electrostatic field,which is also validated by the PIC modeling results.Based on this analytical model,influences of the key physical parameters,including the initial electron temperature and number density,plasma width and the externally applied electric voltage,on the ratio of the extracted ions are predicted.The calculated results show that a higher applied electric potential,smaller initial plasma number density and plasma width lead to a higher ratio of the extracted ions during the first stage;while in this stage,the initial electron temperature shows little effect on it.Meanwhile,more ions will be extracted before the plasma collapse once a higher electric potential is applied.The theoretical model presented in this paper is helpful not only for a deep understanding to the charged particle transport mechanisms for a bounded decaying plasma under an applied electrostatic field,but also for an optimization of the ion extraction process in practical applications.展开更多
In this paper, we describe a possible method for predicting the earthquakes, which is based on simultaneous recording of the intensity of fluxes of neutrons and charged particles by detectors, commonly used in nuclear...In this paper, we describe a possible method for predicting the earthquakes, which is based on simultaneous recording of the intensity of fluxes of neutrons and charged particles by detectors, commonly used in nuclear physics. These low-energy particles originate from radioactive nuclear processes in the Earth＇s crust. The variations in the particle flux intensity can be the precursor of the earth- quake. A description is given of an electronic installation that records the fluxes of charged particles in the radial direction, which are a possible response to the accumulated tectonic stresses in the Earth＇s crust. The obtained results showed an increase in the intensity of the fluxes for 10 or more hours before the occurrence of the earthquake. The previous version of the installation was able to indicate for the possibility of an earthquake （Maksudov et al. in Instrum Exp Tech 58：130-131, 2015）, but did not give information about the direction of the epicenter location. In this regard, the installation was modified by adding eight directional detectors. With the upgraded setup, we have received both the predictive signals, and signals determining the directions of the location of the forthcoming earthquake, starting 2-3 days before its origin.展开更多
The search for dark portal particles is a prominent topic at the frontier of particle physics.We present a simulation study of an experiment suitable for searching for scalar portal particles at the Huizhouηfactory.T...The search for dark portal particles is a prominent topic at the frontier of particle physics.We present a simulation study of an experiment suitable for searching for scalar portal particles at the Huizhouηfactory.The high-intensity proton beam from HIAF and a high event-rate spectrometer are suggested to conduct this experiment,both of which are well-suited for the discovery of new physics.Under a conservative estimation,ηevents could be produced during a one-month operation of the experiment.The hadronic production ofηmesons(p+^(7)Li→ηX)was simulated at a beam energy of 1.8 GeV using the GiBUU event generator.We searched for light dark scalar particles through rare decay channels,namelyη→Sπ^(0)→π^(+)π^(-)π^(0)andη→Sπ^(0)→e^(+)e^(-)e^(0).The detection efficiencies of the channels and the spectrometer resolutions were studied in the simulation.We also present the projected upper limits of the decay branching ratios of the dark scalar particle and the projected sensitivities to the model parameters.展开更多
We justify and extend the standard model of elementary particle physics by generalizing the theory of relativity and quantum mechanics. The usual assumption that space and time are continuous implies, indeed, that it ...We justify and extend the standard model of elementary particle physics by generalizing the theory of relativity and quantum mechanics. The usual assumption that space and time are continuous implies, indeed, that it should be possible to measure arbitrarily small intervals of space and time, but we ignore if that is true or not. It is thus more realistic to consider an extremely small “quantum of length” of yet unknown value <em>a</em>. It is only required to be a universal constant for all inertial frames, like<em> c</em> and <em>h</em>. This yields a logically consistent theory and accounts for elementary particles by means of four new quantum numbers. They define “particle states” in terms of modulations of wave functions at the smallest possible scale in space-time. The resulting classification of elementary particles accounts also for dark matter. Antiparticles are redefined, without needing negative energy states and recently observed “anomalies” can be explained.展开更多
It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It ...It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It is the purpose of this paper to calculate the charges and the size of the electron neutrino, the muon neutrino, and the tau neutrino based on data available of their rest masses using the charges and rest masses of the electron, muon, and tau leptons from the Standard Model of Particle Physics Table. We base our calculations on the premise that Energy can create both Mass and Charge. Charge by itself is not conserved in any process that produces neutrinos. Only Total Energy is conserved.展开更多
We initiate the study of exotic Higgs decays to long-lived particles(LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-base...We initiate the study of exotic Higgs decays to long-lived particles(LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-based search strategy involving the reconstruction of displaced secondary vertices and the imposition of selection cuts appropriate for eliminating the largest irreducible backgrounds. The projected sensitivity is broadly competitive with that of the LHC and potentially superior at lower LLP masses. In addition to forecasting branching ratio limits, which may be freely interpreted in a variety of model frameworks, we interpret our results in the parameter space of a Higgs portal Hidden Valley and various incarnations of neutral naturalness, illustrating the complementarity between direct searches for LLPs and precision Higgs coupling measurements at future lepton colliders.展开更多
The decay of 20Na of astrophysical reactions has been studied deeply via 20Ne(p, n)20Na reaction. A new β-delayed α decay with α energy of 5 896 ± 6 keV and relative intensity of 0. 002 4 ± 0. 000 3 was d...The decay of 20Na of astrophysical reactions has been studied deeply via 20Ne(p, n)20Na reaction. A new β-delayed α decay with α energy of 5 896 ± 6 keV and relative intensity of 0. 002 4 ± 0. 000 3 was discovered. At the same time the 16O recoiling in β+-delayed α decay of 20Na was observed in experiment for the first time. From these, it is inferred that a β-delayed low energy α decay of 20Na with energy of-780 keV and relative intensity of -1.4 was mixed in 16O recoiling. In 16O recoiling and the low energy α decay, the energy loss for low energy charged particles through matter was discussed in detail. At last, two methods for discriminating the β-delayed low energy α decay of 20Na were proposed.展开更多
Open plasma stealth technology excited by radionuclides is known to have several problems:(1)owing to disturbance from airflow,the plasma distribution is unstable.(2)The plasma is highly dependent on the atmosphere;th...Open plasma stealth technology excited by radionuclides is known to have several problems:(1)owing to disturbance from airflow,the plasma distribution is unstable.(2)The plasma is highly dependent on the atmosphere;therefore,it is difficult to modulate in target stealth.(3)Concerns regarding radiation harassment prevent the application of this method.To avoid these problems,an enclosed plasma stealth method is introduced.Via simulation on an infinite conducting plate,this method was found to effectively solve the above concerns,which may offer a new approach for the practical application of plasma stealth technology excited by radionuclides,especially for small-satellite stealth because of its lightweight and selfprovided plasma.展开更多
The discovery of Higgs particle established the success of Standard Model,but there are still unsolved problems such as the origin of neutrino mass whose existence has been confirmed by the oscillation experiments.The...The discovery of Higgs particle established the success of Standard Model,but there are still unsolved problems such as the origin of neutrino mass whose existence has been confirmed by the oscillation experiments.The electric charge neutrality provides the possibility that neutrino could be Majorana particle whose anti-particle is itself.This leads to the possibility of a special nuclear decay called neutrinoless double beta decay(here after 0νββ).Its half-life can be expressed in a simple form for neutrino mass mechanism which is supposed to be the dominant mechanism of the decay。展开更多
The voltage decay of lithium-rich layered oxides(LLOs)is still one of the key challenges for their application in commercial battery although these materials possess the advantages of high specific capacity and low co...The voltage decay of lithium-rich layered oxides(LLOs)is still one of the key challenges for their application in commercial battery although these materials possess the advantages of high specific capacity and low cost.In this work,the relationship between voltage decay and tap density of LLOs has been focused.The voltage decay can be significantly suppressed with the increasing tap density as well as the homogenization of the primary or secondary particle size of agglomerated spherical LLOs.Experimental results have shown that an extreme small voltage decay of 0.98 m V cycle^(-1)can be obtained through adjusting the tap density of agglomerated spherical LLOs to 1.99 g cm^(-3),in which the size of primary and secondary particles are uniform.Our work offers a new insight towards the voltage decay and capacity fading of LLOs through precursor preparation process,promoting their application in the real battery in the future.展开更多
The special property of the actinide mass region is that nuclei belonging to this group are radioactive and undergo different ground state processes,such as alpha decay,cluster radioactivity(CR),heavy particle radioac...The special property of the actinide mass region is that nuclei belonging to this group are radioactive and undergo different ground state processes,such as alpha decay,cluster radioactivity(CR),heavy particle radioactivity(HPR),and spontaneous fission(SF).In this study,the probable radioactive decay modes of the heavy mass region(Z=89−102)are studied within the framework of the preformed cluster model(PCM).In the PCM,the radioactive decay modes are explored in terms of the preformation probability(P0)and penetration probability(P)at the turning point Ra,where the penetration of fragments is initiated[Ra=RT(touching state)+ΔR(neck length parameter)].First,the alpha decay half-lives are calculated for light and heavy nuclei,and Ra points are obtained by optimizing the neck length parameter.These Ra points are further employed to fix the Q-value dependent turning point(Ra(Q)).Then,using the(Ra(Q))relation,the decay half-lives are computed,and the calculated results are compared with the available theoretical and experimental data.The isotopical trend of P0 and P is studied with respect to the mass number of the parent and daughter nucleus,respectively.The CR and HPR channels are also explored,and a comparison of calculated data is conducted with the available literature.Comparative analysis of the fragmentation potential and preformation probability is carried out for alpha decay and SF.The mass distribution of the nuclei is studied as a function of fragment mass(A2)by considering the spherical and hot-compact deformation of the decaying fragments.Finally,the most probable fission fragments are identified using the fragmentation structure,and the corresponding fission fragment total kinetic energy of the identified fragments is calculated and compared with available data,wherever applicable.展开更多
The neutrinoless double-beta （0vββ） decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass （m）ee- We put for...The neutrinoless double-beta （0vββ） decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass （m）ee- We put forward a novel ＇coupling-rod＇ diagram to describe （m）ee in the complex plane, by which the effects of the neutrino mass ordering and CP-violating phases on （m）ee are intuitively understood. We show that this geometric language allows us to easily obtain the maximum and minimum of I（m）eel. It remains usable even if there is a kind of new physics contributing to （m）ee, and it can also be extended to describe the effective Majorana masses （m）eμ, （m）eτ, （m）μμ, （m）,μτ and （m）ττ which may appear in some other lepton-number violating processes.展开更多
We examine the two-pion Hanbury-Brown-Twiss （HBT） interferometry for the particle-emitting source produced in heavy ion collisions at HIRFL-CSR energy. The source evolution is described by relativistic hydrodynamics...We examine the two-pion Hanbury-Brown-Twiss （HBT） interferometry for the particle-emitting source produced in heavy ion collisions at HIRFL-CSR energy. The source evolution is described by relativistic hydrodynamics with three kinds of equations of state for chemical equilibrium （CE）, chemical freeze-out （CFO）, and partial chemical equilibrium （PCE） models, respectively. We investigate the effects of particle decay, multiple scattering, and source collective expansion on the two-pion interferometry results. We find that the HBT radii of the evolution source for the CFO and PCE The HBT lifetime for the CFO model is smaller than those models are smaller than that for the CE model. for the PCE and CE models. The particle decay increases the HBT radius and lifetime while the source expansion decreases the HBT radius. The multiple scattering effect on the HBT results can be neglected based on our model calculations.展开更多
The Standard Model （SM） Higgs boson was predicted by theorists in the 1960s during the development of the electroweak theory. Prior to the startup of the CERN Large Hadron Collider （LHC）, experimental searches fou...The Standard Model （SM） Higgs boson was predicted by theorists in the 1960s during the development of the electroweak theory. Prior to the startup of the CERN Large Hadron Collider （LHC）, experimental searches found no evidence of the Higgs boson. In July 2012, the ATLAS and CMS experiments at the LHC reported the discovery of a new bosun in their searches for the SM Higgs boson. Subsequent experimental studies have revealed the spin-0 nature of this new boson and found its couplings to SM particles consistent to those of a Higgs boson. These measurements confirmed the newly discovered boson is indeed a Higgs bosun. More measurements will be performed to compare the properties of the Higgs boson with the SM predictions.展开更多
文摘We present here a two-step method of classification and calculation for decay rates in the Standard Model. The first step is a phenomenological classification method, which is an extended and improved schematic experimental formula for decay width originally introduced by Chang. This schematic formula separates decays into seven classes. Furthermore, from it is derived a process-specific interaction energy m<sub>X</sub>. The second step is a numerical calculation method, which calculates this interaction energy m<sub>X</sub> numerically by minimization of action from the Lagrangian of the process, from which follows the decay width via the phenomenological formula. The Lagrangian is based on an extension of the Standard Model, the extended SU(4)-preon-model. A comparison of numerically calculated and observed decay widths for a large selection of decays shows a good agreement.
基金the National Natural Science Foundation of China(Grant No.11775128)。
文摘The spatiotemporal evolutions of a one-dimensional collisionless decaying plasma bounded by two electrodes with an externally applied electrostatic field are studied by theoretical analyses and particle-in-cell(PIC)simulations with the ion extraction process in a laser-induced plasma as the major research background.Based on the theoretical analyses,the transport process of the charged particles including electrons and ions can be divided into three stages:electron oscillation and ion matrix sheath extraction stage,sheath expansion and ion rarefaction wave propagation stage and the plasma collapse stage,and the corresponding criterion for each stage is also presented.Consequently,a complete analytical model is established for describing the ion extraction flux at each stage during the decaying of the laser-induced plasmas under an electrostatic field,which is also validated by the PIC modeling results.Based on this analytical model,influences of the key physical parameters,including the initial electron temperature and number density,plasma width and the externally applied electric voltage,on the ratio of the extracted ions are predicted.The calculated results show that a higher applied electric potential,smaller initial plasma number density and plasma width lead to a higher ratio of the extracted ions during the first stage;while in this stage,the initial electron temperature shows little effect on it.Meanwhile,more ions will be extracted before the plasma collapse once a higher electric potential is applied.The theoretical model presented in this paper is helpful not only for a deep understanding to the charged particle transport mechanisms for a bounded decaying plasma under an applied electrostatic field,but also for an optimization of the ion extraction process in practical applications.
文摘In this paper, we describe a possible method for predicting the earthquakes, which is based on simultaneous recording of the intensity of fluxes of neutrons and charged particles by detectors, commonly used in nuclear physics. These low-energy particles originate from radioactive nuclear processes in the Earth＇s crust. The variations in the particle flux intensity can be the precursor of the earth- quake. A description is given of an electronic installation that records the fluxes of charged particles in the radial direction, which are a possible response to the accumulated tectonic stresses in the Earth＇s crust. The obtained results showed an increase in the intensity of the fluxes for 10 or more hours before the occurrence of the earthquake. The previous version of the installation was able to indicate for the possibility of an earthquake （Maksudov et al. in Instrum Exp Tech 58：130-131, 2015）, but did not give information about the direction of the epicenter location. In this regard, the installation was modified by adding eight directional detectors. With the upgraded setup, we have received both the predictive signals, and signals determining the directions of the location of the forthcoming earthquake, starting 2-3 days before its origin.
文摘The search for dark portal particles is a prominent topic at the frontier of particle physics.We present a simulation study of an experiment suitable for searching for scalar portal particles at the Huizhouηfactory.The high-intensity proton beam from HIAF and a high event-rate spectrometer are suggested to conduct this experiment,both of which are well-suited for the discovery of new physics.Under a conservative estimation,ηevents could be produced during a one-month operation of the experiment.The hadronic production ofηmesons(p+^(7)Li→ηX)was simulated at a beam energy of 1.8 GeV using the GiBUU event generator.We searched for light dark scalar particles through rare decay channels,namelyη→Sπ^(0)→π^(+)π^(-)π^(0)andη→Sπ^(0)→e^(+)e^(-)e^(0).The detection efficiencies of the channels and the spectrometer resolutions were studied in the simulation.We also present the projected upper limits of the decay branching ratios of the dark scalar particle and the projected sensitivities to the model parameters.
文摘We justify and extend the standard model of elementary particle physics by generalizing the theory of relativity and quantum mechanics. The usual assumption that space and time are continuous implies, indeed, that it should be possible to measure arbitrarily small intervals of space and time, but we ignore if that is true or not. It is thus more realistic to consider an extremely small “quantum of length” of yet unknown value <em>a</em>. It is only required to be a universal constant for all inertial frames, like<em> c</em> and <em>h</em>. This yields a logically consistent theory and accounts for elementary particles by means of four new quantum numbers. They define “particle states” in terms of modulations of wave functions at the smallest possible scale in space-time. The resulting classification of elementary particles accounts also for dark matter. Antiparticles are redefined, without needing negative energy states and recently observed “anomalies” can be explained.
文摘It is the current belief of the Physics Community that neutrinos are bereft of Charge because of Conservation of Charge in decay processes such as Beta Decay and are point particles with no physical size or shape. It is the purpose of this paper to calculate the charges and the size of the electron neutrino, the muon neutrino, and the tau neutrino based on data available of their rest masses using the charges and rest masses of the electron, muon, and tau leptons from the Standard Model of Particle Physics Table. We base our calculations on the premise that Energy can create both Mass and Charge. Charge by itself is not conserved in any process that produces neutrinos. Only Total Energy is conserved.
基金Supported by the US Department of Energy under the Early Career Award DE-SC0014129 and the Cottrell Scholar Program through the Research Corporation for Science Advancement
文摘We initiate the study of exotic Higgs decays to long-lived particles(LLPs) at proposed future lepton colliders, focusing on scenarios with displaced hadronic final states. Our analysis entails a realistic tracker-based search strategy involving the reconstruction of displaced secondary vertices and the imposition of selection cuts appropriate for eliminating the largest irreducible backgrounds. The projected sensitivity is broadly competitive with that of the LHC and potentially superior at lower LLP masses. In addition to forecasting branching ratio limits, which may be freely interpreted in a variety of model frameworks, we interpret our results in the parameter space of a Higgs portal Hidden Valley and various incarnations of neutral naturalness, illustrating the complementarity between direct searches for LLPs and precision Higgs coupling measurements at future lepton colliders.
基金Project supported by the Chinese Academy of Sciences and the National Natural Science Foundation of China.
文摘The decay of 20Na of astrophysical reactions has been studied deeply via 20Ne(p, n)20Na reaction. A new β-delayed α decay with α energy of 5 896 ± 6 keV and relative intensity of 0. 002 4 ± 0. 000 3 was discovered. At the same time the 16O recoiling in β+-delayed α decay of 20Na was observed in experiment for the first time. From these, it is inferred that a β-delayed low energy α decay of 20Na with energy of-780 keV and relative intensity of -1.4 was mixed in 16O recoiling. In 16O recoiling and the low energy α decay, the energy loss for low energy charged particles through matter was discussed in detail. At last, two methods for discriminating the β-delayed low energy α decay of 20Na were proposed.
文摘Open plasma stealth technology excited by radionuclides is known to have several problems:(1)owing to disturbance from airflow,the plasma distribution is unstable.(2)The plasma is highly dependent on the atmosphere;therefore,it is difficult to modulate in target stealth.(3)Concerns regarding radiation harassment prevent the application of this method.To avoid these problems,an enclosed plasma stealth method is introduced.Via simulation on an infinite conducting plate,this method was found to effectively solve the above concerns,which may offer a new approach for the practical application of plasma stealth technology excited by radionuclides,especially for small-satellite stealth because of its lightweight and selfprovided plasma.
文摘The discovery of Higgs particle established the success of Standard Model,but there are still unsolved problems such as the origin of neutrino mass whose existence has been confirmed by the oscillation experiments.The electric charge neutrality provides the possibility that neutrino could be Majorana particle whose anti-particle is itself.This leads to the possibility of a special nuclear decay called neutrinoless double beta decay(here after 0νββ).Its half-life can be expressed in a simple form for neutrino mass mechanism which is supposed to be the dominant mechanism of the decay。
基金financially supported by the Beijing Natural Science Foundation(JQ19003)National Key R&D Program of China(grant no.2018YFB0104300)+4 种基金National Natural Science Foundation of China(grant no 51622202,21603009,and 21875007)Beijing Natural Science Foundation(B)(KZ201910005002)Beijing Natural Science Foundation(L182009)Project of Youth Talent Plan of Beijing Municipal Education Commission(CIT&TCD201804013)High-grade discipline construction of Beijing(PXM2019-014204-500031)。
文摘The voltage decay of lithium-rich layered oxides(LLOs)is still one of the key challenges for their application in commercial battery although these materials possess the advantages of high specific capacity and low cost.In this work,the relationship between voltage decay and tap density of LLOs has been focused.The voltage decay can be significantly suppressed with the increasing tap density as well as the homogenization of the primary or secondary particle size of agglomerated spherical LLOs.Experimental results have shown that an extreme small voltage decay of 0.98 m V cycle^(-1)can be obtained through adjusting the tap density of agglomerated spherical LLOs to 1.99 g cm^(-3),in which the size of primary and secondary particles are uniform.Our work offers a new insight towards the voltage decay and capacity fading of LLOs through precursor preparation process,promoting their application in the real battery in the future.
基金Financial support from the Department of Science and Technology (DST),New Delhi,India in the form of a research project grant (CRG/2021/001144)
文摘The special property of the actinide mass region is that nuclei belonging to this group are radioactive and undergo different ground state processes,such as alpha decay,cluster radioactivity(CR),heavy particle radioactivity(HPR),and spontaneous fission(SF).In this study,the probable radioactive decay modes of the heavy mass region(Z=89−102)are studied within the framework of the preformed cluster model(PCM).In the PCM,the radioactive decay modes are explored in terms of the preformation probability(P0)and penetration probability(P)at the turning point Ra,where the penetration of fragments is initiated[Ra=RT(touching state)+ΔR(neck length parameter)].First,the alpha decay half-lives are calculated for light and heavy nuclei,and Ra points are obtained by optimizing the neck length parameter.These Ra points are further employed to fix the Q-value dependent turning point(Ra(Q)).Then,using the(Ra(Q))relation,the decay half-lives are computed,and the calculated results are compared with the available theoretical and experimental data.The isotopical trend of P0 and P is studied with respect to the mass number of the parent and daughter nucleus,respectively.The CR and HPR channels are also explored,and a comparison of calculated data is conducted with the available literature.Comparative analysis of the fragmentation potential and preformation probability is carried out for alpha decay and SF.The mass distribution of the nuclei is studied as a function of fragment mass(A2)by considering the spherical and hot-compact deformation of the decaying fragments.Finally,the most probable fission fragments are identified using the fragmentation structure,and the corresponding fission fragment total kinetic energy of the identified fragments is calculated and compared with available data,wherever applicable.
基金Supported by National Natural Science Foundation of China(11135009)
文摘The neutrinoless double-beta （0vββ） decay is a unique process used to identify the Majorana nature of massive neutrinos, and its rate depends on the size of the effective Majorana neutrino mass （m）ee- We put forward a novel ＇coupling-rod＇ diagram to describe （m）ee in the complex plane, by which the effects of the neutrino mass ordering and CP-violating phases on （m）ee are intuitively understood. We show that this geometric language allows us to easily obtain the maximum and minimum of I（m）eel. It remains usable even if there is a kind of new physics contributing to （m）ee, and it can also be extended to describe the effective Majorana masses （m）eμ, （m）eτ, （m）μμ, （m）,μτ and （m）ττ which may appear in some other lepton-number violating processes.
基金Supported by National Natural Science Foundation of China (10575024,10775024)
文摘We examine the two-pion Hanbury-Brown-Twiss （HBT） interferometry for the particle-emitting source produced in heavy ion collisions at HIRFL-CSR energy. The source evolution is described by relativistic hydrodynamics with three kinds of equations of state for chemical equilibrium （CE）, chemical freeze-out （CFO）, and partial chemical equilibrium （PCE） models, respectively. We investigate the effects of particle decay, multiple scattering, and source collective expansion on the two-pion interferometry results. We find that the HBT radii of the evolution source for the CFO and PCE The HBT lifetime for the CFO model is smaller than those models are smaller than that for the CE model. for the PCE and CE models. The particle decay increases the HBT radius and lifetime while the source expansion decreases the HBT radius. The multiple scattering effect on the HBT results can be neglected based on our model calculations.
基金supported by the Director,Office of Science,Offices of High Energy and Nuclear Physics of the U.S.Department of Energy(Grant No.DE-AC02-05CH11231)
文摘The Standard Model （SM） Higgs boson was predicted by theorists in the 1960s during the development of the electroweak theory. Prior to the startup of the CERN Large Hadron Collider （LHC）, experimental searches found no evidence of the Higgs boson. In July 2012, the ATLAS and CMS experiments at the LHC reported the discovery of a new bosun in their searches for the SM Higgs boson. Subsequent experimental studies have revealed the spin-0 nature of this new boson and found its couplings to SM particles consistent to those of a Higgs boson. These measurements confirmed the newly discovered boson is indeed a Higgs bosun. More measurements will be performed to compare the properties of the Higgs boson with the SM predictions.
