NPAC (Nuclear/Particle/Astro/Cosmo) Forum

IceCube neutrino telescope recently discovered astrophysical neutrinos in the energy range from 10 TeV to 3 PeV. This discovery challenged existed theoretical models due to unexpected observation of soft 1/E^{2.5} neutrino spectrum. Together with limits from diffuse gamma-ray flux measured with Fermi LAT this excluded most of existed theoretical predictions. In my talk I'll discuss significance of the galactic component observation in the 4 years IceCube data. Also I'll review theoretical models, which can explain observed data both with Galactic and extra-galactic sources of neutrinos. Finally, I'll present model, which at the same time explain Ultra-High Energy Cosmic Ray protons, astrophysical neutrinos and diffuse gamma-ray background.

Host: 
Francis Halzen
Speaker: Dmitri Semikoz APC Paris

 

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Room and Building: 
5310 Chamberlin Hall

I will present the main elements of our independent studies of the high-energy events seen above 28TeV by IceCube, arXiv:1404.0017 and arXiv:1502.02649. I will cover the physics involved, and show the effect of modelling and assumptions on the conclusions one can reach about the flavor composition, spectrum, and background rates. I will compare our results and methodology with the official IceCube studies, and discuss future prospects.

Host: 
Carlos Arguelles Delgado
Speaker: Aaron Vincent Institute for Particle Physics Phenomenology , Durham University

 

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Room and Building: 
4274 Chamberlin Hall
Neutrinos created in one flavour state (electron, muon, and tau) can oscillate into a different one as they propagate. Such oscillations imply that states of a given flavour are really superpositions of three mass states, with the rate of oscillations depending on the difference in squared masses of these states. These differences have two characteristic scales, one measurable with solar neutrinos, and one with neutrinos from atmospheric and accelerator sources, so early experiments assumed mixing between only two flavours.

With larger and more precise detectors the full three-flavour structure can to begin to be probed. The mass ordering of the three states is accessible via neutrino interactions with matter as they propagate through the Earth, whilst the possibility that neutrino oscillations violate charge parity symmetry can be probed via electron neutrino appearance in a muon neutrino beam. In this talk I will discuss an update to the MINOS atmospheric neutrino analysis, and discuss CHIPS: an R&D experiment aiming to build a large water Cherenkov detector in a flooded mine pit in Northern Minnesota, which deployed a small prototype in the summer of 2014.
Host: 
Kael Hanson
Speaker: Andy Perch University College London

 

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Room and Building: 
5280 Chamberlin Hall
Speaker: Bryce Littlejohn Illinois Institute of Technology

 

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Room and Building: 
5310 Chamberlin Hall
Inclusive fluxes of muons and neutrinos in the atmosphere provide a continuous source of information about the spectrum and composition of cosmic rays interacting with air nuclei. Furthermore, measurements of the fluxes allow us to learn more about hadronic interactions in phase space regions not accessible at high-energy colliders. Using an accurate and flexible solution of the coupled cascade equations, called matrix-method, it is possible to study numerically the connection between atmospheric muon observations and measurements made at fixed-target or collider experiments. I will present the status of lepton
flux calculations using different interaction models and primary cosmic ray flux assumptions. Emphasis is put on the role of hadronic interactions by discussing the importance of different phase-space regions, particle species and interaction energies for the prediction of atmospheric lepton fluxes.
Host: 
Paolo Desiati
Speaker: Anatoli Fedynitch Karlsruhe

 

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Room and Building: 
5280 Chamberlin Hall
The first hints of new physics at the LHC may come in the form of extremely short-lived particles which decay instantly to particles in the standard model. These decays could appear as an excess of events in any number of channels. Until recently, searches for such an excess have often neglected decays through charm quarks, owing to the lack of an efficient charm jet identification algorithm.

I will introduce several supersymmetric models where decays through charm quarks are preferred. These searches motivated the development of a lifetime-based charm jet identification algorithm. After discussing this algorithm, I will present the results from two scalar quark searches, where charm jet identification played a central role in extending the previous experimental limits
Host: 
Stefan Westerhoff
Speaker: Dan Guest Yale University

 

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4274 Chamberlin

In this talk I shall narrate our plans of building a new underground laboratory facility in southern India called India-based neutrino observatory (INO). A 50 kilo-ton magnetised Iron CALorimeter (ICAL)is one of the first experiments proposed to be housed in this observatory for the study of neutrino properties like mass hierarchy, precision measurement of oscillation parameters etc. using the atmospheric neutrinos. The details of this ICAL project and its present status will also be covered in this talk.

Host: 
Justin Vandenbrouke
Speaker: Bannanje Sripathi Acharya Tata Institute

 

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Room and Building: 
5310 Chamberlin Hall

Work on VHE gamma-ray astronomy using the Atmospheric Cherenkov Technique started in India way back in 1969,soon after the discovery of pulsars. Over the years, steady improvements in telescope hardware have led to increase in the sensitivity and collection area as well as reduction in the energy threshold of the experiments. The latest in this series of experiments is the HiGRO project located at very high altitude (4.3km), at Hanle in the Ladakh region of Himalayas. In the first phase of this project 7 telescope array called HAGAR was installed the year 2008. It is an array of wavefront sampling non- imaging telescopes having a threshold energy of about 200 GeV for gamma-rays. This is the first ACT array operating at very high altitudes. A 21-m imaging telescope (called MACE), built by BARC group, will be commissioned at the same site adjascent to HAGAR array in this year. With MACE, the threshold energy of gamma-rays is expec to be about a few tens of GeV. Regular observations of galactic and extra galactic objects using HAGAR are going on since October 2008. I shall describe the status the HiGRO project at Hanle and the recent results obtained using the HAGAR array.

Host: 
Mike Duvernois
Speaker: Bannanje Sripathi Acharya Tata Institute

 

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Room and Building: 
5280 Chamberlin Hall

The Fermi Bubbles are a pair of giant lobes at the heart of the Milky Way, extending roughly 50 degrees north and south of the Galactic Center, and emitting photons with energies up to 100 GeV. This previously unknown structure could be evidence for past activity of the central supermassive black hole. I will first summarize what we have learned about the bubbles through multi-wavelength observations and numerical simulations. We discovered the bubbles while searching for potential signal of dark matter particle annihilation toward the Galactic Center, using data from the Fermi Gamma-ray Space Telescope. More than six years successful operation of Fermi has proved the great potential of studying astrophysics, cosmology, and fundamental physics through gamma-ray sky. I will highlight the search of dark matter particles using gamma-ray and cosmic-ray observations, which motivated three future space telescopes: DAMPE, HERD, and PANGU. Together with the next generation ground-based Cherenkov telescopes e.g. CTA and LHAASO, we will be able to measure gamma-ray photons with energies from MeV to above PeV with much improved sensitivity. Finally, I will comment on a future plan to search for primordial gravitational waves produced from inflation in the very beginning of the Universe.

Host: 
Dasu
Speaker: Meng Su MIT, Joint MIT Pappalardo and NASA Einstein Fellow

 

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Room and Building: 
4274 Chamberlin Hall

Advances in low noise cryogenic amplifiers and the commercialization of microwave technology have not only improved astrophysical measurements, but also enabled exquisitely sensitive laboratory experiments. I will discuss a number of benchtop experiments that utilize radio astronomy techniques and technology to make measurements that are important for astroparticle physics. The experiments I cover will include searches for dark matter axions using electronics with noise limited only by quantum mechanical effects, searches for light exotic beyond-the-standard-model particles, and a precision measurement of beta decay energies that could be used to determine the neutrino mass scale.

Host: 
Dasu
Speaker: Gray Rybka University of Washington

 

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Room and Building: 
4274 Chamberlin Hall

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