Investigating the Apparent Teleconnection between Cosmic-Ray Muon Flux over Jamaica and Large-Scale Climate Phenomena That Impact the Caribbean

The apparent teleconnection between cosmic-ray muon flux over a base point in the Caribbean is discussed against the background of an extensive record of indices representing large-scale climatic phenomena, but limited cosmic-ray muon flux data. Many investigators have shown that large-scale climate phenomena influence sub-seasonal and seasonal climate variability, especially in the northern hemisphere and their impacts on the Caribbean are well documented. These climatic phenomena that impact the Caribbean include, but are not limited to, the El Nino Southern Oscillation, the Quasi-Biennial Oscillation, the North Atlantic Oscillation, and the Arctic Oscillation which is now being investigated. Although strong statistical correlation between variables over non-contiguous regions are not absolute as proof of teleconnections, the correlation strength can be used as an indication of its existence. The data gathered at the Mona Campus of the University of the West Indies, in Jamaica, using a simple QuarkNet 6000 muon detector over the period September 2011 to September 2013, showed an apparent significant relationship with these climatic indices. This suggests that cosmic-ray muon flux might be linked to the behavior of the climate phenomena and therefore can be used as a climate or meteorological index over the Caribbean.

Cosmic-ray exposure histories of two Antarctic meteorites from Chinese collections and the Guangmingshan and Zhuanghe chondrites

Concentrations of noble gases of two Antarctic meteorites (GRV 98002, 98004) from Chinese collections, and the Guangmingshan and Zhuanghe chondrites were measured. Based on the petrography and mineralogy of these meteorites, and production rates of the cosmogenic nuclides, we calculated cosmic-ray exposure and gas retention ages of the four chondrites. Exposure ages of the four chondrites are 0.052 Ma 0.008 Ma (GRV 98004, H5), 17.0 Ma 2.5 Ma (GRV98002, L5), 3.8 Ma 0.6 Ma (Zhuanghe, H5), and 68.9 Ma 10 Ma (Guangmingshan, H5), respectively. The exposure age of GRV 98004 is the lowest value of Antarctic meteorites reported up to date; while that of Guangmingshan is higher than other Chinese meteorites of H-group. Both GRV 98002 and Zhuanghe have low 4He concentrations, probably due to shock effects or solar heating at orbits with small perihelion distances during cosmic-ray exposure. On the other hand, losses of cosmogenic 3He and 4He are correlated with both GRV 98002 and Guangmingshan.

Cosmic-ray exposure and gas retention ages of the Guang-mingshan(H5) chondrite

Isotopic compositions of noble gases from the Guangmingshan chondrite were analyzed. Based on the analyses of cosmogenic nuclei, cosmic-ray exposure age of the meteorite is (65±10.0) Ma (3He), (80±12) Ma (21Ne) and (65±10.0) Ma (38Ar), with an average of 70 Ma. This is the highest exposure age of H-group ordinary chondrites. Gas retention ages of K-Ar and U, Th-4He are (4230±100) Ma and (3300±60) Ma, respectively. The smaller ages of 3He than 21Ne and 4He than Ar suggest that both 3He and 4He lost together. This is probably related to a solar heating effect of a meteorite with a small perihelion during the last exposure period.

Noble gas and cosmic-ray exposure age of Juancheng chondrite

The analytical results of noble gase in recently fallen Juancheng chondrite indicate that cosmic-ray ages of cosmogenic nuclei of 3He, 21Ne and 38Ar are 5.1, 5.0 and 5.8 Ma, respectively, averaging 5.3 Ma. The gas retention ages radiogenic nuclei of 4He and 40Ar are 3200 and 4 200 Ma, respectively. The average cosmic-ray age shows that it has occurred at breakup of the meteoroid from its parent body by impact before 5.3 Ma.

Applicability of cosmic-ray neutron sensor for measuring soil moisture at the agricultural-pastoral ecotone in northwest China

Accurate monitoring of soil moisture is crucial in hydrological and ecological studies.Cosmic-ray neutron sensors(CRNS)measure area-average soil moisture at field scale,filling a spatial scale gap between in-situ observations and remote sensing measurements.However,its applicability has not been assessed in the agricultural-pastoral ecotone,a data scarce semiarid and arid region in Northwest China(APENC).In this study,we calibrated and assessed the CRNS(the standard N0 method)estimates of soil moisture.Results show that Pearson correlation coefficient,RP,and the root mean square error(RMSE)between the CRNS soil moisture and the gravimetric soil moisture are 0.904 and less than 0.016 m3 m–3,respectively,indicating that the CRNS is able to estimate the area-average soil moisture well at our study site.Compared with the in-situ sensor network measurements(ECH2O sensors),the CRNS is more sensitive to the changes in moisture in its footprint,which overestimates and underestimates the soil moisture under precipitation and dry conditions,respectively.The three shape parameters a0,a1,a2 in the standard calibration equation(N0 method)are not well suited to the study area.The calibrated parameters improved the accuracy of the CRNS soil moisture estimates.Due to the lack of low gravimetric soil moisture data,performance of the calibrated N0 function is still poor in the extremely dry conditions.Moreover,aboveground biomass including vegetation biomass,canopy interception and widely developed biological soil crusts adds to the uncertainty of the CRNS soil moisture estimates.Such biomass impacts need to be taken into consideration to further improve the accuracy of soil moisture estimation by the CRNS in the data scarce areas such as agricultural-pastoral ecotone in Northwest China.

Dark matter, neutrino mass, cutoff for cosmic-ray neutrino, and the Higgs boson invisible decay from a neutrino portal interaction

We study an effective theory beyond the standard model(SM) where either of the two additional gauge singlets, a Majorana fermion and a real scalar, constitutes all or some fraction of dark matter. In particular, we focus on the masses of the two singlets in the range of O(10) MeV-O(10) GeV with a neutrino portal interaction, which plays an important role not only in particle physics but also in cosmology and astronomy. We point out that the thermal dark matter abundance can be explained by(co-)annihilation, where the dark matter with a mass greater than 2 GeV can be tested in future lepton colliders, CEPC, ILC, FCC-ee and CLIC, in the light of the Higgs boson invisible decay. When the gauge singlets are lighter than O(100) MeV, the interaction can affect the neutrino propagation in the universe due to its annihilation with cosmic background neutrino into the gauge singlets. Although in this case it can not be the dominant dark matter, the singlets are produced by the invisible decay of the Higgs boson at such a rate which is fully within reach of future lepton colliders. In particular, a high energy cutoff of cosmic-ray neutrino,which may account for the non-detection of Greisen-Zatsepin-Kuzmin(GZK) neutrino or the non-observation of the Glashow resonance, can be set. Interestingly, given the cutoff and the mass(range) of WIMPs, a neutrino mass can be"measured" kinematically.

FURTHER PROBE OF COSMIC-RAY DOUBLE LEAKY BOX MODEL

In recent years, the measurements of cosmic-ray nuclei and electrons with higher accuracy have made it possible to study further the cosmic-ray propagation models. According to the current theories about cosmic-ray origin, the energy spectra of nuclei and electrons are assumed to have the same shapes, i.e. q（E）=AE0-γ, here A is a constant, E is the energy and γ0 is the spectral index of source. However, the fittings to the data of nuclei and electrons in the single leaky box model give γ0p=2.0 for nuclei and γ0e=2.7 for electrons, respectively, which do not agree with the theories of cosmic-ray origin.

Study of BESⅢ MUC offine software with cosmic-ray data

Cosmic-ray data of 90 M events have been collected and used for calibration,alignment as well as detector tuning. A special tracking algorithm for the BESⅢ muon counter is developed and verified with Monte-Carlo simulation and then further confirmed with the cosmic-ray data. The obtained strip resolutions are in good agreement with the design values. A new alignment approach for the BESⅢ muon counter is confirmed with the cosmic-ray data and proposed to be used in future analysis of experimental data.

Construction and cosmic-ray test of the new inner drift chamber for BESIII

A new inner drift chamber has been built which can replace the aged part of the BESIII drift chamber when needed. The design of the new inner drift chamber can minimize the ineffective area in the very forward and backward region and hence reduce the background event rate. With this design, the new inner drift chamber is expected to have a longer lifetime and improved performance due to the lower occupancy. The endplates and the cylinder were machined with high precision. Wire stringing was performed after the mechanical structure was assembled, and good quality of wire stringing was ensured by measurement of the tension and leakage current of the wires. After completion of the physical construction of the new chamber, a cosmic-ray test was carried out to test its performance. The results of the cosmic-ray test show that the new inner chamber achieves a spatial resolution of127 μm and a d E/dx resolution of 6.4%, which satisfies the design specifications.

Feasibility study of cosmic-ray componentsmeasurement by using a scintillating fiber tracker in space

Purpose The application of traditional silicon strip detectors in space experiments often suffers from heat and power consumption limitations when a large area has to be instrumented.Recently,a scintillating fiber detector with SiPM readout was proposed and adopted by ground high-energy experiments.Its excellent performance in track measurement and mechanical flexibility makes it a prospective candidate for large-area tracking detectors in the next-generation space experiments.This paper mainly focuses on its performance in cosmic-ray charge measurement.Methods A fast Geant4 simulation for a single tracker module was developed and compared with the beam test results.The non-uniformity of the detector response was studied.Moreover,a full tracker simulation using a variety of typical cosmic ray nuclei was implemented.The performance of a fiber tracker with multiple layers was evaluated.Results and conclusion The comparison between the simulation results and the beam test data of protons and helium nuclei shows a good agreement.The non-uniformity study reveals the strong dependence of the detector signal on the position and inclination angle of the incident particles.Then,a corresponding correction algorithm was developed and applied in the following data analysis.The preliminary result shows that the charge measurement capability of the fiber tracker composed of 9 XY superlayers is comparable to that of the AMS-02 inner tracker,which consists of 7 layers of double-sided silicon micro-strip ladders.This paper discusses the feasibility of using fiber trackers to measure cosmic ray charges and provide a guide for the optimization of detector design.

Updated study on multi-TeV cosmic-ray modulation with the Tibet Ⅲ air shower array using the east-west method

We study the sidereal and solar time modulation of multi-TeV cosmic rays using the east-west method with Tibet air shower array data taken from November 1999 to December 2008. The statistics are twice the amount used in our previous paper. In this analysis, the amplitude of the observed sidereal time modulation is about 0.1%, and the modulation shows an excess from about 4 to 7 hours and a deficit around 12 hours in local sidereal time. The sidereal time modulation has a weak dependence on the primary energy of the cosmic rays. However, the solar time modulation shows a large energy dependence. We find that the solar time modulation is fairly consistent with the prediction of the Compton-Getting effect for high-energy samples （6.2TeV and 12.0TeV）, but exceeds the prediction for the low-energy sample （4.0TeV）. Such a discrepancy may be due to the solar modulation or the characteristics of the experimental device in the near threshold energy.

Tuning of the cosmic-ray test system of the BESⅢ drift chamber

The BESⅢ drift chamber and its subsystems need a cosmic-ray test after the chamber construction to check the chamber construction quality,testing the joint operation of the whole system and the performance of the chamber.The noise performance,drift time and charge measurements,and the scanning of channels were examined specifically.The preliminary results of the test indicate that the whole system works well.

Study of imaging unknown objects by cosmic-ray muons

Introduction Cosmic-ray muon imaging is a kind of nondestructive detection technology which can be used to detect unknown objects in geological exploration,civil engineering and nuclear safety.Transmission imaging and scattering tomography schemes are studied.Method The transmission scheme uses a multilayer detector to measure the direction of a cosmic-ray muon passing through an object.The scattering scheme involves placing two detectors upstream and downstream of the object to record the incident and exit directions of the muon passing through the object.The effect of the detector resolution on the imaging clarity of transmission imaging was studied.The applicable scenarios of the two schemes were analyzed.Results The results by calculating show that in the transmission imaging of a hundred-meter object,a spatial resolution of 2.5 m can be achieved,and Cu and Fe can be discriminated with a density difference of 1.1 g/cm3.Scattering tomography is mainly suitable for meter-level objects,which can detect 0.2 m chamber and distinguish 0.05 m heavy metal blocks in rock.

Investigating the Apparent Link between Cosmic Ray Muon Flux, Sudden Stratospheric Warming and Dry Season Rainfall over Jamaica

The Jamaican primary dry season extends from November-April with the driest period being January-March each year. Examination of the rainfall records over several decades reveal months that experienced a sharp increase in rainfall while sometimes they are drier than normal. During this dry season, some of the weather systems that impact the island significantly are cold fronts, highs pressure systems and troughs that migrate from the mainland USA. Major Sudden Stratospheric Warmings (SSW) occur routinely north of 60°N and severely impact weather over the North American continent. The islands of the Greater Antilles also experience inclement weather during this period as weather systems migrate southwards and impact the Caribbean. Severe winter weather due to the increase frequency and intensity of storms related to SSW events over North America is important to the Jamaican economy as tourists escape harsh winters by travelling to the island. Predicting the variability of rainfall during the primary dry season is therefore important as it has significant implications for event planning, tourism and agriculture. Cosmic-ray Muon flux has been found to be positively correlated with the atmospheric effective temperature used to indicate the occurrence of SSW events. Current research investigates the relationship between cosmic-ray Muon flux, SSW events and primary dry season rainfall. Our findings suggest that a significant change in rainfall occur over Jamaica during the primary dry season on average 29 days after the central date or on average 15 days after the SSW events end. Our study also suggests apparent similarities in the behaviour of cosmic-ray Muon flux over Jamaica to those when major SSW occurs at high latitudes. We therefore argue that the Muon detectors at low latitudes have practical use with respect to identifying SSWs and merits further study.

Muon flux measurement at China Jinping Underground Laboratory

China Jinping Underground Laboratory(CJPL)is ideal for studying solar,geo-,and supernova neutrinos.A precise measurement of the cosmic-ray background is essential in proceeding with R&D research for these MeV-scale neutrino experiments.Using a 1-ton prototype detector for the Jinping Neutrino Experiment(JNE),we detected 264 high-energy muon events from a 645.2-day dataset from the first phase of CJPL(CJPL-I),reconstructed their directions,and measured the cosmic-ray muon flux to be (3.53±0.22_stat.±0.07_sys.)×-10^(-10)cm^(-2).The observed angular distributions indicate the leakage of cosmic-ray muon background and agree with simulation data accounting for Jinping mountain's terrain.A survey of muon fluxes at different laboratory locations,considering both those situated under mountains and those down mine shafts,indicates that the flux at the former is generally a factor of (4±2) larger than at the latter,with the same vertical overburden.This study provides a convenient back-of-the-envelope estimation for the muon flux of an underground experiment.

ARE THE PRIMARY COSMIC RAY ELECTRONS PRODUCED BY SQUEEZING IN THE COLLAPSE PROCESS OF COMPACT STAR?

The origin of cosmic ray is an important topic in the high energy astrophysics. The generally accepted viewpoint is that supernova events are the most important sources of the high energy cosmic-ray electrons. Various mechanisms of particle acceleration have

Measurement of muon-induced neutron yield at the China Jinping Underground Laboratory

Solar,terrestrial,and supernova neutrino experiments are subject to muon-induced radioactive background.The China Jinping Underground Laboratory(CJPL),with its unique advantage of a 2400 m rock coverage and long distance from nuclear power plants,is ideal for MeV-scale neutrino experiments.Using a 1-ton prototype detector of the Jinping Neutrino Experiment(JNE),we detected 3 43 high-energy cosmic-ray muons and(7.86±3.97)muon-induced neutrons from an 820.28-day dataset at the first phase of CJPL(CJPL-I).Based on the muon-induced neutrons,we measured the corresponding muon-induced neutron yield in a liquid scintillator to be(3.44±1.86_(stat.)±0.76_(syst.))×10^(-4) μ^(-1)g^(-1)cm^(2) at an average muon energy of 340 GeV.We provided the first study for such neutron background at CJPL.A global fit including this measurement shows a power-law coefficient of(0.75±0.02) for the dependence of the neutron yield at the liquid scintillator on muon energy.

COSMOGENIC^(10)Be,NOBLE GASES AND IRRADIATION HISTORY OF CHONDRITES ZHAODONG,NAN YANG PAO,LUNAN AND ZAOYANG

10Be is mainly produced in meteorite by spallation reactions of cosmic ray particles with oxygen, magnesium, silicon or nitrogen in it. The threshold energy is above 500 MeV. The half lifetime of 10Be in between 26Al and 53Mn is 1.6 Ma. Thus the possibility of routine determination of 10Be in a large number of meteorites constitutes an improvement in studying the exposure conditions of

Searching for sub-MeV boosted dark matter from xenon electron direct detection

Direct detection experiments tend to lose sensitivity in searches for sub-MeV light dark matter candidates due to the threshold of recoil energy.However,such light dark matter particles could be accelerated by energetic cosmic rays,such that they could be detected with existing detectors.We derive constraints on the scattering of a boosted light dark matter particle and electron from the XENON100/1T experiment.We illustrate that the energy dependence of the cross section plays a crucial role in improving both the detection sensitivity and also the complementarity of direct detection and other experiments.

Studies of detector cells for a hadronic calorimeter based on plastic scintillators

In this paper,we study variations of a plastic scintillator tile coupled to silicon photomultiplier via a dome-shaped cavity originally developed in the CALICE collaboration.Four kinds of plastic scintillator detector cells with different sizes based on the structure were studied for applications in analog readout highly granular hadronic calorimeter(AHCAL)in future circular electron positron collider(CEPC)project.The responses to cosmic rays of the detector cells could reach 33.89 p.e./MIPs(minimum ionizing particles).The good results of both response uniformity and MIP detection efficiency(above 95%)show that the detector cells with larger sizes(40×40×3 and 50×50×3 mm^(3))could provide an option for AHCAL detector cells of CEPC detectors.