Cosmology in the presence of multiple light moduli

Acharya, B. S.; Dhuria, Mansi; Ghosh, Diptimoy; Maharana, Anshuman; Muia, Francesco

doi:10.1088/1475-7516/2019/11/035

Cited by 33 publications

(29 citation statements)

References 64 publications

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“…Crab nebula photon spectrum, according to different theoretical models, continues up to 100-400 TeV [38]. At these energies, it would be detected by HAWC [39], CTA [40,41], Carpet-2 [42], TAIGA [43], LHAASO [44]. Detection of photons from Crab (or other galactic sources) in these energy range may increase the bound (34) up to the level M LV > 5 × 10 14 GeV.…”

Section: Discussionmentioning

confidence: 99%

Photon splitting constraint on Lorentz invariance violation from Crab Nebula spectrum

Astapov¹,

Satunin²

2019

J. Cosmol. Astropart. Phys.

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We calculate the decay width of the photon splitting into three photons in a model of quantum electrodynamics with broken Lorentz invariance. We show that this process can lead to a cut-off in the very-high-energy part of a photon spectra of astrophysical sources. We obtain the 95% CL bound on the Lorentz violating mass scale for photons from the analysis of the very-high-energy part of the Crab Nebula spectrum, obtained by HEGRA. This bound improves previous constraints by more than an order of magnitude.

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Section: Discussionmentioning

confidence: 99%

Photon splitting constraint on Lorentz invariance violation from Crab Nebula spectrum

Astapov¹,

Satunin²

2019

J. Cosmol. Astropart. Phys.

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“…Additionally, a minimum of 10 signal events are required; we also require that the number of signal events exceeds the number of background events. Other sensitivity curves were taken from [47] (see also [48]) and denote the differential sensitivity of Fermi LAT and atmospheric Cherenkov telescopes (ACT) [49,50] (see Figure 5 (left) of [16] for the meaning of these curves). We conclude that the proposed new γ-ray instrument has the sensitivity several times greater than the Fermi LAT one in the wide energy range 100 MeV-100 GeV and could provide a natural low-energy extension for IACT such as the CTA array [49,50] or LHAASO [51].…”

Section: Em Cascades From Nearby Sourcesmentioning

confidence: 99%

Intergalactic γ-ray propagation: basic ideas, processes, and constraints

Dzhatdoev

Khalikov

Podlesnyi

et al. 2019

J. Phys.: Conf. Ser.

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We review extragalactic γ-ray propagation models with emphasis on the electromagnetic (EM) cascade process in the magnetized expanding Universe. We consider cascades initiated by primary protons of ultra-high energy accelerated by blazars and show that the observable spectrum is similar to the universal spectrum of a purely EM cascade. We also present a detailed calculation of the observable angular distribution for the case of EM cascades developing from relatively nearby (<20 Mpc) sources. Finally, we calculate the point-like source differential sensitivity of a novel liquid Argon time projection chamber γ-ray telescope and show that its sensitivity is several times better than the Fermi LAT sensitivity in the 100 MeV -100 GeV energy range. 1 hereafter simply "electrons" 2 below we do not consider primary nuclei, thus the photodissociation process is not relevant

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“…The use of SiPMs as the focal-plane camera pixels of Cherenkov telescopes was first realized by the FACT telescope [2]. As of 2019, several SiPM camera prototypes are also being developed for the Cherenkov Telescope Array (CTA) [3] with the aim to build compact and less expensive cameras with thousands of pixels that can have a high tolerance to bright moon nights.…”

Section: Introductionmentioning

confidence: 99%

Characterization of SiPM Optical Crosstalk and Its Dependence on the Protection-Window Thickness

Nakamura

Okumura

Tajima

et al. 2019

Proceedings of the 5th International Workshop on New Photon-Detectors (PD18)

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Owing to their high photon detection efficiency, compactness, and low operating voltage, silicon photomultipliers (SiPMs) have found widespread application in many fields, including medical imaging, particle physics, and high-energy astrophysics. However, the so-called optical crosstalk (OCT) phenomenon of SiPMs is a major drawback to their adoption. Secondary infrared photons are emitted inside the silicon substrate spontaneously after the avalanche process caused by the primary incident photons, and they can be detected by the surrounding photodiodes. As a result large output pulses that are equivalent to multiple photoelectrons are observed with a certain probability (OCT rate), even for single-photon events, making the charge resolution worse and increasing the rate of accidental triggers by single-photon events in applications such as atmospheric Cherenkov telescopes. In our previous study, we found that the OCT rates of single-channel SiPMs was dependent on the thickness of their protection resin window, which may be explained by photon propagation inside the resin. In the present study, we measured the OCT rate of a multichannel SiPM and those of neighboring channels caused by photon propagation. Both OCT rates were found to be dependent on the protection-window thickness. We report our OCT measurements of a multichannel SiPM and comparisons with a ray-tracing simulation.

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Cosmology in the presence of multiple light moduli

Cited by 33 publications

References 64 publications

Photon splitting constraint on Lorentz invariance violation from Crab Nebula spectrum

Photon splitting constraint on Lorentz invariance violation from Crab Nebula spectrum

Intergalactic γ-ray propagation: basic ideas, processes, and constraints

Characterization of SiPM Optical Crosstalk and Its Dependence on the Protection-Window Thickness

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