Solar Hidden Photon Search

Monthly Notices of the Royal Astronomical Society

The surface detector (SD) of the Telescope Array (TA) experiment allows us to detect indirectly photons with energies of the order of 1018 eV and higher, and to separate photons from the cosmic ray background. In this paper, we present the results of a blind search for point sources of ultra-high-energy (UHE) photons in the Northern sky using the TA SD data. The photon-induced extensive air showers are separated from the hadron-induced extensive air shower background by means of a multivariate classifier based upon 16 parameters that characterize the air shower events. No significant evidence for the photon point sources is found. The upper limits are set on the flux of photons from each particular direction in the sky within the TA field of view, according to the experiment’s angular resolution for photons. The average 95 per cent confidence level upper-limits for the point-source flux of photons with energies greater than 1018, 1018.5, 1019, 1019.5 and 1020 eV are 0.094, 0.029, 0....

1997

Recent developments of those areas of astro-particle physics are discussed that were represented at the HEP97 conference. In particular, the current status of direct and indirect dark-matter searches and of TeV neutrino and gamma-ray astronomy will be reviewed.

Advances in Space Research, 2008

PAMELA is a multipurpose apparatus composed of a series of scintillator counters arranged at the extremities of a permanent magnet spectrometer to provide charge, time-of-flight and rigidity information. Lepton/hadron identification is performed by a silicon-tungsten calorimeter and a Neutron detector placed at the bottom of the device. An Anticounter system is used offline to reject false triggers coming from the satellite. The device was put into orbit on June 15th 2006 in a pressurized container on board the Russian Resurs-DK1 satellite. The satellite is flying along a high inclination (70°), low Earth orbit (350-600 km), allowing to perform measurements in different points and conditions of the geomagnetosphere. PAMELA main goal is a precise measurement of the antimatter (p 80 MeV-190 GeV, e + 50 MeV-270 GeV) and matter (p 80-700 GeV, e À 50 MeV-400 GeV) component of the galactic cosmic rays. In this paper we focus on the capabilites of observations of heliospheric cosmic rays: trapped and semi-trapped particles in the proton and electron belts, solar particle events, Jovian electrons will be studied in the three years of expected mission.

Local interstellar spectra (LIS) for protons, helium and antiprotons are built using the most recent experimental results combined with the state-of-the-art models for propagation in the Galaxy and heliosphere. Two propagation packages, GALPROP and HelMod, are combined to provide a single framework that is run to reproduce direct measurements of cosmic ray (CR) species at different modulation levels and at both polarities of the solar magnetic field. To do so in a self-consistent way, an iterative procedure was developed, where the GALPROP LIS output is fed into HelMod that provides modulated spectra for specific time periods of selected experiments to compare with the data; the HelMod parameters optimization is performed at this stage and looped back to adjust the LIS using the new GALPROP run. The parameters were tuned with the maximum likelihood procedure using an extensive data set of proton spectra from 1997–2015. The proposed LIS accommodate both the low energy interstellar CR spectra measured by Voyager 1 and the high energy observations by BESS, Pamela, AMS-01, and AMS-02 made from the balloons and near-Earth payloads; it also accounts for Ulysses counting rate features measured out of the ecliptic plane. The found solution is in a good agreement with proton, helium, and antiproton data by AMS-02, BESS, and PAMELA in the whole energy range.

arXiv (Cornell University), 2022

The Standard Model of particle physics is a (3) × (2) × (1) gauge theory that can * Speaker

We studied the source regions of 12 solar energetic particle (SEP) events seen between 2010 August and 2012 January at STEREO-A, B, and/or Earth (Advanced Composition Explorer/Solar and Heliospheric Observatory/GOES), when the two STEREO spacecraft were separated by about 180 • . All events were associated with flares (C1 to X6) and fast coronal mass ejections and, except for one, accompanied by type II radio bursts. We have determined the arrival times of the SEPs at the three positions. Extreme ultraviolet (EUV) waves, observed in the 195 Å and 193 Å channels of STEREO and the Solar Dynamics Observatory, are tracked across the Sun to determine their arrival time at the photospheric source of open field lines connecting to the spacecraft. There is a good correlation between the EUV wave arrival times at the connecting footpoints and the SEP onset times. The delay time between electron onset and the EUV wave reaching the connecting footpoint is independent of distance from the flare site. The proton delay time increases with distance from the flare site. In three of the events, secondary flare sites may have also contributed to the wide longitudinal spread of SEPs.

Astroparticle Physics, 2007

The use of large area particle detectors, which can only be accommodated on the Earth's surface, is vital for measuring the low fluxes of high energy particles accelerated in the vicinity of the Sun. The mystery of particle acceleration in the Universe cannot be explored without the understanding of solar particle accelerators. The energy spectra of highest energy solar particles, as measured by the surface detectors, will shed light on these universal processes of high-energy particle acceleration at numerous galactic and extragalactic sites. Detected at Earth, energetic particles also can provide extremely cost-effective information on the key characteristics of the interplanetary disturbances. Because cosmic rays are fast this information travels rapidly and can be useful for space weather forecasting. Taking into account that only very few of a great number of solar flares and coronal mass ejections (CME) produce intensive ion fluxes, the socalled solar energetic particle events, it is not only critical to alert clients about the arrival of the most severe radiation storms, but also to minimize the number of false alarms against events which are not severe enough to cause damage. Using examples of extreme solar events from the 23rd solar cycle, we present experimental results and analysis of the sensitivity of the secondary cosmic ray flux, registered at middle latitudes to the various parameters of the solar particle ''beams'' incident on the Earth's atmosphere.

Physical Review Letters, 1992

We have searched for a flux of axions produced in the sun by exploiting their conversion to x-rays in a static magnetic field.

Astrophys Space Sci, 1972

It is suggested that the minimum mass of a star at the time of its formation is approximately 0.01 M| Making use of this fact and the stellar mass function F(M) oc M-a, it is found that the hidden mass (or the missing mass) in the solar neighborhood may be explained by the presence of a large number of invisible stars of very low mass (0.01 M o < M< 0.07 Mo).

Journal of Cosmology and Astroparticle Physics

Propagation of ultra-high energy photons in the solar magnetosphere gives rise to cascades comprising thousands of photons. We study the cascade development using Monte Carlo simulations and find that the photons in the cascades are spatially extended over millions of kilometers on the plane distant from the Sun by 1 AU. We estimate the chance of detection considering upper limits from current cosmic rays observatories in order to provide an optimistic estimate rate of 0.002 events per year from a chosen ring-shaped region around the Sun. We compare results from simulations which use two models of the solar magnetic field, and show that although signatures of such cascades are different for the models used, for practical detection purpose in the ground-based detectors, they are similar.