Journal Club

Seminar Room

If you want to propose a paper, you can contact Supratim Das Bakshi (sdb AT

Friday 14th of April, 2023



Title:  Ultra-peripheral collisions of charged hadrons in extensive air showers [2303.16042] 


Authors:   Manuel MasipIvan RosarioSergio J. Sciutto


Abstract:  We discuss the electromagnetic collisions of high energy protons, pions and kaons with atmospheric nuclei. In particular, we use the equivalent photon approximation to estimate (i) the diffractive collisions where the projectile scatters inelastically off a nucleus, and (ii) the usual radiative processes (bremsstrahlung, pair production and photonuclear interactions) of these charged hadrons in the air. We then include the processes in the simulator AIRES and study how they affect the longitudinal development of extensive air showers. For 109-11 GeV proton primaries we find that they introduce a very small reduction (below 1%) in the average value of both Xmax  and ΔXmax . At a given shower age (relative slant depth from Xmax), these electromagnetic processes do not change significantly the number of muons or the total energy carried by electrons and photons, increased by just 1% the muon-to-(γ+e) signal at the ground level.


Presented by:  Manuel Masip




Title: Higgs portal, fermionic dark matter, and a Standard Model like Higgs at 125 GeV [1203.2064]


Authors:   Laura Lopez-HonorezThomas SchwetzJure Zupan



Abstract: We show that fermionic dark matter (DM) which communicates with the Standard Model (SM) via the Higgs portal is a viable scenario, even if a SM-like Higgs is found at around 125 GeV. Using effective field theory we show that for DM with a mass in the range from about 60 GeV to 2 TeV the Higgs portal needs to be parity violating in order to be in agreement with direct detection searches. For parity conserving interactions we identify two distinct options that remain viable: a resonant Higgs portal, and an indirect Higgs portal. We illustrate both possibilities using a simple renormalizable toy model. proposal.
Presented by:   Miguel Gutiérrez