Potential for Constraining Propagation Parameters of Galactic Cosmic Rays with the High Energy Cosmic-radiation Detection Facility on Board China's Space Station

Precise measurements of the spectra of secondary and primary cosmic rays are crucial for understanding the origin and propagation of those energetic particles.The High Energy Cosmic-radiation Detection(HERD)facility on board China's Space Station,which is expected to operate in 2027,will push the direct and precise measurements of cosmic-ray fluxes up to PeV energies.In this work,we investigate the potential of HERD for studying the propagation of cosmic rays using measurements of boron,carbon,and oxygen spectra.We find that,compared with the current results,the new HERD measurements can improve the accuracy of the propagation parameters by 8%–40%.The constraints on the injection spectra at high energies will also be improved.

Intrinsic Wave Velocity Propagation:A Novel Parameter for Assessing the Effect of Anthracycline Chemotherapy Agents on Cardiac Diastolic Function in Breast Cancer Patients

Objective Anthracycline chemotherapeutic agents have significant cardiotoxicity.The present study emphasized the effect of anthracycline chemotherapy drugs on left ventricular(LV)myocardial stiffness in breast cancer patients by measuring the intrinsic wave velocity propagation(IVP),and evaluating the potential clinical value of IVP in detecting early LV diastolic function impairment.Methods A total of 68 newly diagnosed breast cancer patients,who were treated with anthracycline-based chemotherapy,were analyzed.Transthoracic echocardiography was performed at baseline(T0),and after 1,2,3,4 and 8 chemotherapeutic cycles(T1,T2,T3,T4 and T5,respectively).Then,the IVP,LV strain parameters[global longitudinal strain(GLS),longitudinal peak strain rate at systole(LSRs),longitudinal peak strain rate at early diastole(LSRe),longitudinal peak strain rate at late diastole(LSRa),and the E/LSRe ratio],and conventional echocardiographic parameters were obtained and further analyzed.A relative reduction of>15%in GLS was considered a marker of early LV subclinical dysfunction.Results Compared to the T0 stage,IVP significantly increased at the T1 stage.However,there were no significant changes in GLS,LSRs,or LSRe between the T0 and T1 stages.These parameters significantly decreased from the T2 stage.LSRa started to significantly decrease at the T5 stage,and the E/LSRe ratio started to significantly increase at the T3 stage(all P<0.05).At the T0 stage,IVP(AUC=0.752,P<0.001)had a good predictive value for LV subclinical dysfunction after chemotherapy.Conclusions IVP is a potentially sensitive parameter for the early clinical assessment of anthracycline-related cardiac diastolic impairment.

Prevalence and associated factors of corneal blindness in Ningxia in northwest China

AIM:To describe the prevalence and demographic characteristics of corneal blindness in an urban and rural region of Ningxia,located in the northwest part of China.METHODS:A stratified,randomized sampling procedure was employed in the study,including urban and rural area of all age group.Visual acuity,anterior segment and ocular fundus were checked.Related factor of corneal disease,including age,gender,education status,ethnic group,location and occupation,were identified according to uniform customized protocol.An eye was defined to be corneal blindness if the visual acuity was【20/400 due to a corneal disease.RESULTS:Three thousand individuals(1290 from urban area and 1710 from rural area)participated in the investigation,with a response rate of 80.380%.The prevalence of corneal blindness was 0.023%in both eyes and 0.733%in at least one eye.The blindness in at least one eye with varied causes was present in 106participants(3.533%)and in bilateral eyes in 34participants(1.133%).The corneal diseases accounted for 20.754%of blindness in at least one eye and 20.588%of bilateral blindness.The prevalence of corneal disease was higher in older and Han ethnic group,especially those who occupied in agriculture and outdoor work.People with corneal blindness were more likely to be older and lower education.Rural population were more likely to suffer from bilateral corneal blindness than the urban population in≥59-year group(χ2=6.716,P=0.019).Infectious,trauma and immune corneal disease were the three leading causes of corneal disease.Trauma cornealdisease was more likely leading to blindness in one eye.However,infectious and immune corneal diseases make more contribution to the bilateral corneal blindness.CONCLUSION:Corneal blindness is a significant burden of in Ningxia population,encompassing a variety of corneal infections and trauma;the majority of those were avoidable.Health promotion strategies and good hygienic conditions have to be developed.

Evaluation of Left Ventricular Function by Three-Dimensional Speckle-Tracking Echocardiography in Patients with Chronic Kidney Failure

Objective:To establish a quantitative evaluation of the left ventricle's systolic function in patients with chronic kidney failure(CKF)by three-dimensional speckle-tracking echocardiography.Methods:Two-dimensional and three-dimensional transthoracic echocardiography was performed on 30 patients with CKF.The ejection fraction,mass and global peak longitudinal strain,global circumferential strain,global area strain,and global radial strain of the left ventricle were calculated.Results:The ejection fraction,mass and global peak longitudinal strain(GLS),global circumferential strain(GCS),global area strain(GAS),and global radial strain(GRS)in the CKF group were significantly lower than those in the control group.Simultaneously,the GLS,GCS,GAS and GRS were well correlated with the ejection fraction.For patients with normal ejection fraction in the CKF group,the GLS,GCS,GAS and GRS were lower than those in the control group,while the left ventricular mass was significantly higher in CKF patients than in the control group.For patients with hypertension in the CKF group,ejection fraction,GLS,GCS,GAS and GRS calculated using three-dimensional echocardiography were significantly lower than those in patients with normal blood pressure;however,the myocardial mass was higher.Conclusions:The parameters(GLS,GCS,GAS and GRS)calculated using three-dimensional speckle-tracking software were lower in the CKF group.Simultaneously,the left ventricular mass was higher in CFK patients than in the control group,thus showing that the myocardial contraction function was impaired and that myocardial remodeling had occurred.

Klein–Nishina Effect and the Cosmic Ray Electron Spectrum

Radiative energy losses are very important in regulating the cosmic ray electron and/or positron(CRE) spectrum during their propagation in the Milky Way. Particularly, the Klein–Nishina(KN) effect of the inverse Compton scattering(ICS) results in less efficient energy losses of high-energy electrons, which is expected to leave imprints on the propagated electron spectrum. It has been proposed that the hardening of CRE spectra around 50 GeV observed by Fermi-LAT, AMS-02, and DAMPE could be due to the KN effect. We show in this work that the transition from the Thomson regime to the KN regime of the ICS is actually quite smooth compared with the approximate treatment adopted in some previous works. As a result, the observed spectral hardening of CREs cannot be explained by the KN effect. It means that an additional hardening of the primary electrons spectrum is needed. We also provide a parameterized form for the accurate calculation of the ICS energy-loss rate in a wide energy range.

Constraints on axion-like particles from the observation of Galactic sources by the LHAASO

High-energy photons may oscillate with axion-like particles(ALPs)when they propagate through the Milky Way's magnetic field,resulting in an alteration in the observed photon energy spectrum.Ultra-high energy gamma-ray spectra,measured by the Large High Altitude Air Shower Observatory(LHAASO)up to O(1)PeV,provide a promising opportunity to investigate the ALP-photon oscillation effect.In this study,we utilize the gamma-ray spectra of four Galactic sources measured by the LHAASO,that is,the Crab Nebula,LHAASO J2226+6057,LHAASO J1908+0621,and LHAASO J1825-1326,to explore this effect.We employ the CLsmethod to set constraints on the ALP parameters.Our analysis of the observations of the four sources reveals that the ALPphoton coupling gaγis constrained to be smaller than 1.4×10^(-1)0GeV^(-1)for an ALP mass of~4×10^(-7)eV at 95%C.L.Combining the observations of the Crab Nebula from the LHAASO and other experiments,we find that the ALP-photon coupling may be set to approximately 7.5×10^(-11)GeV^(-1)for an ALP mass of~4×10^(-7)eV,which is similar to the CAST constraint.

Impact of a nearby subhalo on the constraint of dark matter annihilation from cosmic ray antiprotons

Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way.The potential existence of a nearby subhalo could have important implications for our understanding of dark matter(DM)annihilation.In this study,we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum.By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo,we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section.The impacts of the concentration model and the subhalo probability distribution have been considered.We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE e+spectrum at~1.4 TeV and find that the current AMS-02 antiproton results do not limit this contribution.

Interpretations of the cosmic ray secondary-toprimary ratios measured by DAMPE

Precise measurements of the boron-to-carbon and boron-to-oxygen ratios by DAMPE show clear hardenings around 100 GeV/n,which provide important implications on the production,propagation,and interaction of Galactic cosmic rays.In this work we investigate a number of models proposed in literature in light of the DAMPE findings.These models can roughly be classified into two classes,driven by propagation effects or by source ones.Among these models discussed,we find that the re-acceleration of cosmic rays,during their propagation,by random magnetohydrodynamic waves may not reproduce sufficient hardenings of B/C and B/O,and an additional spectral break of the diffusion coefficient is required.The other models can properly explain the hardenings of the ratios.However,depending on simplifications assumed,the models differ in their quality in reproducing the data in a wide energy range.The models with significant re-acceleration effect will under-predict low-energy antiprotons but over-predict low-energy positrons,and the models with secondary production at sources over-predict high-energy antiprotons.For all models high-energy positron excess exists.

Nearby source interpretation of differences among light and medium composition spectra in cosmic rays

Recently the AMS-02 reported the precise measurements of the energy spectra of medium-mass compositions(Neon,Magnesium,Silicon)of primary cosmic rays,which reveal different properties from those of light compositions(Helium,Carbon,Oxygen).Here we propose a nearby source scenario,together with the background source contribution,to explain the newly measured spectra of cosmic ray Ne,Mg,Si,and particularly their differences from that of He,C,O.Their differences at high energies can be naturally accounted for by the element abundance of the nearby source.Specifically,the abundance ratio of the nearby source to the background of the Ne,Mg,Si elements is lower by a factor of~1.7 than that of the He,C,O elements.Such a diference could be due to the abundance difference of the stellar evolution of the progenitor star or the acceleration process/environment,of the nearby source.This scenario can simultaneously explain the high-energy spectral softening features of cos-mic ray spectra revealed recently by CREAM/NUCLEON/DAMPE,as well as the energy-dependent behaviors of the large scale anisotropies.It is predicted that the dipole anisotropy amplitudes below PeV energies of the Ne,Mg,Si group are smaller than that of the He,C,O group,which can be tested with future measurements.

Chapter 2 Galactic Gamma-ray Sources

In theγ-ray sky,the highest fluxes come from Galactic sources:supernova remnants(SNRs),pulsars and pulsar wind nebulae,star forming regions,binaries and micro-quasars,giant molecular clouds,Galactic center,and the large extended area around the Galactic plane.The radiation mechanisms ofγ-ray emission and the physics of the emitting particles,such as the origin,acceleration,and propagation,are of very high astrophysical significance.A variety of theoretical models have been suggested for the relevant physics,and emission with energies E≥10^(14) eV are expected to be crucial in testing them.In particular,this energy band is a direct window to test at which maximum energy a particle can be accelerated in the Galactic sources and whether the most probable source candidates such as Galactic center and SNRs are“PeVatrons”.Designed aiming at the very high energy(VHE,>100 GeV)observation,LHAASO will be a very powerful instrument in these astrophysical studies.Over the past decade,great advances have been made in the VHEγ-ray astronomy.More than 170 VHEγ-ray sources have been observed,and among them,42 Galactic sources fall in the LHAASO field-of-view.With a sensitivity of 10 milli-Crab,LHAASO can not only provide accurate spectra for the knownγ-ray sources,but also search for new TeV-PeVγ-ray sources.In the following sub-sections,the observation of all the Galactic sources with LHAASO will be discussed in details.

Expected LHAASO sensitivity to decaying dark matter signatures from dwarf galaxies gamma-ray emission

As a next-generation complex extensive air shower array with a large field of view,the large high altitude air shower observatory(LHAASO)is very sensitive to the very-high-energy gamma rays from^300 GeV to 1 PeV and may thus serve as an important probe for the heavy dark matter(DM)particles.In this study,we make a forecast for the LHAASO sensitivities to the gamma-ray signatures resulting from DM decay in dwarf spheroidal satellite galaxies(dSphs)within the LHAASO field of view.Both individual and combined limits for 19 dSphs incorporating the uncertainties of the DM density profile are explored.Owing to the large effective area and strong capability of the photon-proton discrimination,we find that LHASSSO is sensitive to the signatures from decaying DM particles above O(1)TeV.The LHAASO sensitivity to the DM decay lifetime reaches O(1026)∼O(1028)s for several decay channels at the DM mass scale from 1 TeV to 100 TeV.

Nearby dark matter subhalo that accounts for the DAMPE excess

The precise spectrum of electrons and positrons at high energies plays an important role in understanding their origin. DArk Matter Particle Explorer has reported their first measurement of the e^+e^- spectrum from 25 GeV to 4.6 TeV. This spectrum reveals a tentative peak at ~1.4 TeV, which requires a nearby source of e^+e^-. In this work, we study the properties of a large nearby dark matter subhalo that accouns for this spectral peak, such as its mass and distance from Earth, for different concentration models. We compare spectra of the sources in 3FGL with that from DM annihilation in the subhalo, and find ten candidates that have comparable gamma-ray spectra. However, according to the N-body simulation, the probability that such a large subhalo is close enough to Earth is less than 0.1%.

Chapter 5 Dark Matter and New Physics Beyond the Standard Model with LHAASO

In order to reveal the nature of dark matter,it is crucial to detect its non-gravitational interactions with the standard model particles.The traditional dark matter searches focused on the so-called weakly interacting massive particles.However,this paradigm is strongly constrained by the null results of current experiments with high precision.Therefore there is a renewed interest of searches for heavy dark matter particles above TeV scale.The Large High Altitude Air Shower Observatory(LHAASO)with large effective area and strong background rejection power is very suitable to investigate the gamma-ray signals induced by dark matter annihilation or decay above TeV scale.In this document,we review the theoretical motivations and background of heavy dark matter.We review the prospects of searching for the gamma-ray signals resulted from dark matter in the dwarf spheroidal satellites and Galactic halo for LHAASO,and present the projected sensitivities.We also review the prospects of searching for the axion-like particles,which are a kind of well motivated light pseudo-scalars,through the LHAASO measurement of the very high energy gamma-ray spectra of astrophysical sources.

Searching for axion-like particles with the blazar observations of MAGIC and Fermi-LAT

In this study,we explore the axion-like particle(ALP)-photon oscillation effect in the γ-ray spectra of the blazars Markarian 421(Mrk 421) and PG 1553+113,which are measured by the Major Atmospheric Gamma Imaging Cherenkov Telescopes(MAGIC) and Fermi Large Area Telescope(Fermi-LAT) with high precision.The Mrk421 and PG 1553+113 observations of 15 and five phases are used in the analysis,respectively.We find that the combined analysis with all the 15 phases improves the limits of the Mrk 421 observations.For the selected blazar jet magnetic field and extragalactic background light models,the combined limit set by the Mrk 421 observations excludes the ALP parameter region with the ALP-photon coupling of g_(aγ)≥2×10^(-11) GeV^(-1) for the ALP mass of~8×10^(-9)≤m_(a)≤2×10^(-7) eV at 95% confidence level.The main uncertainties of the analysis originate from the blazar jet magnetic field model.We also find that the ALP hypothesis can slightly improve the fit to the PG1553+113 results in several parameter regions.We do not set the limit in this case.

Chapter 3 Extra-galactic gamma-ray sources

Extra-galactic gammaray sources,such as gamma-ray bursts,active galactic nuclei,starburst galaxies,are interesting and important targets for LHAASO observations.In this chapter,the prospects of detecting these sources with LHAASO and their physical implications are studied.The upgrade plan for the Water Cherenkov Detector Array(WCDA),which aims to enhance the detectability of relatively lower energy photons,is also presented.In addition,a study on constraining the extragalactic background light with LHAASO observation of blazars is presented.

Exploring fermionic multiplet dark matter through precision measurements at the CEPC

New physics could be explored through loop effects using the precision measurements at the Circular Electron Positron Collider(CEPC)owing to its clean collision environment and high luminosity.In this paper,we focus on two dark matter models that involve additional electroweak fermionic multiplets.We calculate their one-loop corrections in five processes,i.e.,e^(+)e^(-)→μ^(+)μ^(-),Zh,W^(+)W^(-),ZZ,and,Zγ,and investigate the corresponding signatures at the CEPC with the projected sensitivity.We observe that the detectable parameter regions of these processes are complementary.The combined analysis shows that the mass of dark matter m_(χ^(0)_(1))in these two models can be probed up to-150GeV and-450GeV,respectively,at a 95%confidence level.

Galactic cosmic ray propagation: sub-PeV diffuse gamma-ray and neutrino emission

The Tibet ASγexperiment just reported their measurement of sub-PeV diffuse gamma-ray emission from the Galactic disk,with the highest energy up to 957 TeV.These diffuse gamma rays are most likely the hadronic origin by cosmic ray(CR)interaction with interstellar gas in the galaxy.This measurement provides direct evidence to the hypothesis that the Galactic Cosmic Rays(GCRs)can be accelerated beyond PeV energies.In this work,we try to explain the sub-PeV diffuse gamma-ray spectrum with different CR propagation models.We find that there is a tension between the sub-PeV diffuse gamma-ray and the local CR spectrum.To describe the sub-PeV diffuse gamma-ray flux,it generally requires larger local CR flux than measurement in the knee region.We further calculate the PeV neutrino flux from the CR propagation model.Even all of these sub-PeV diffuse gamma rays originate from the propagation,the Galactic Neutrinos(GNs)only account for less than∼15%of observed flux,most of which are still from extragalactic sources.

Galactic cosmic ray propagation: sub-PeV diffuse gamma-ray and neutrino emission

The Tibet ASγexperiment just reported their measurement of sub-PeV diffuse gamma-ray emission from the Galactic disk,with the highest energy up to 957 TeV.These diffuse gamma rays are most likely the hadronic origin by cosmic ray(CR)interaction with interstellar gas in the galaxy.This measurement provides direct evidence to the hypothesis that the Galactic Cosmic Rays(GCRs)can be accelerated beyond PeV energies.In this work,we try to explain the sub-PeV diffuse gamma-ray spectrum with different CR propagation models.We find that there is a tension between the sub-PeV diffuse gamma-ray and the local CR spectrum.To describe the sub-PeV diffuse gamma-ray flux,it generally requires larger local CR flux than measurement in the knee region.We further calculate the PeV neutrino flux from the CR propagation model.Even all of these sub-PeV diffuse gamma rays originate from the propagation,the Galactic Neutrinos(GNs)only account for less than~15%of observed flux,most of which are still from extragalactic sources.

Implications of axion-like particles from the Fermi-LAT and H.E.S.S.observations of PG 1553+113 and PKS 2155−304

We investigate the axion-like particle(ALP)-photon oscillation effect in the high-energy y-ray spectra of PG 1553+113 and PK.S 2155-304 measured by Fermi-LAT and H.E.S.S.The choice of extragalactic background light(EBL)model,which induces the attenuation effect in observed y-ray spectra,affects the ALP implications.For the ordinary EBL model that prefers a null hypothesis,we set constraints on the ALP-photon coupling constant at 95% C.L.as gay 5×10^(-11) GeV^(-1) for the ALP mass 〜10 neV.We also consider the CIBER observation of the cosmic infrared radiation,which shows an excess at wavelengths of -1μm after the substraction of foregrounds.High-energy gamma-rays from extragalactic sources at high redshifts would suffer from a more significant attenuation effect caused by this excess.In this case,we find that the ALP-photon oscillation would improve the fit to the observed spectra of PKS 2155-304 and PG 1553+113 and find a favored parameter region at 95%CL..

Constraining the cosmic ray propagation halo thickness using Fermi-LAT observations of high-latitude clouds

The diffusive halo is a basic characteristic of cosmic ray(CR)propagation and can advance our understanding of many CR-related phenomena and indirect dark matter.The method used to derive the halo size often has degeneracy problems and is thus affected by large uncertainties.The diffuseγrays from high-latitude clouds might shed light on the halo size independently.Because predictions using the spatially dependent propagation(SDP)model have better agreement with the observed CRs than those of the conventional propagation model,in this work,we investigated halo thickness based on the SDP model using Fermi-LATγ-ray observations of high-and intermediatevelocity clouds.We found that to avoid exceeding the relativeγ-ray emissivity in high-latitude clouds,the halo thickness should be in the range of 3.3-9 kpc.Moreover,the spatial morphology ofγ-rays estimated based on the SDP model for different values of the halo thickness are distinctive,which provides us with a tool to determine the halo size.This newly developed model can be tested and tuned using multi-wavelength observations in future studies.