News and events

Events

  • xiangcai_chen_photo Trial lecture: Xiangcai Chen Feb. 28, 2017 10:15 AM

    Doctoral candidate Master in Optics Xiangcai at Department of Physics will give a trial lecture on the given topic: "Challenges in radio wave communication and navigation at auroral latitudes"

  • xiangcai_chen_photo Disputation: Xiangcai Chen Feb. 28, 2017 01:00 PM

    Master in Optics Xiangcai Chen at Department of Physics will be defending the thesis A study of dayside open/closed field line boundary dynamics using simultaneous ground-based optical and HF radar observations for the degree of Philosophiae Doctor (PhD)

  • Cosmic rays: new insights in the precision era Mar. 3, 2017 01:05 PM

    Yoann Génolini, LAPTH Annecy

    Recent experiments (notably PAMELA and, more recently, AMS-02) are ushering us into a new era of measurements of cosmic-ray fluxes with greatly reduced statistical uncertainties. These high precision measurements offer new opportunities for a number of astroparticle problems, such as indirect dark matter searches. In particular, astrophysical anti-particle fluxes are thought to be produced only by collisions of cosmic rays on the interstellar medium, and their relatively low flux makes them a channel of choice to look for rare processes. Nonetheless, the prediction of these expected backgrounds relies on a precise modeling of the cosmic ray propagation and interaction in the Galaxy, usually constrained by « secondary over primary » ratios. I will show that the predictions for the most widely used among these probes, the boron-to-carbon ratio (B/C), strongly depends on underlying assumptions. Under some simplified hypotheses on the propagation scenario, I will present two of our studies reevaluating anti-protons and positrons fluxes in the light of new AMS02 data, and discuss the implications for dark matter. (continued below)

    (The slides will be available here)

  • Calculation of Momentum Distribution Function of a Non-thermal Fermionic Dark Matter Mar. 8, 2017 01:05 PM

    Aritra Gupta, HCRI, Allahabad

    The most widely studied scenario in dark matter phenomenology is the thermal WIMP (Weakly Interacting Massive Particle) scenario. Inspite of numerous efforts to detect WIMP, till now we have no direct evidence for it. A possible explanation for this non-observation of dark matter could be because of its very feeble interaction strength and hence, failing to thermalise with the rest of the cosmic soup. In other words, the dark matter might be of non-thermal origin where the relic density is obtained by the so called freeze-in mechanism. Furthermore, if this non-thermal dark matter is itself produced substantially from the decay of another non-thermal mother particle, then their distribution function may differ in both size and shape from the usual equilibrium distribution. In this talk I will discuss about such a non-thermal (fermionic) dark matter scenario in the light of a new type of U(1)B-L model. The model is interesting, since, besides being anomaly free, it can give rise to neutrino mass by Type II see-saw mechanism. Moreover, we will see, that it can accommodate a non-thermal fermionic dark matter as well. Starting from the collision terms, ... (cont. below)

    (The slides will be available here)

  • New Frontiers in Physics 2017 Aug. 17, 2017 12:00 AM

    The International Conference on new Frontiers in Physics aims to promote scientific exchange and development of novel ideas in science with a particular accent on interdisciplinarity.