NPAC (Nuclear/Particle/Astro/Cosmo) Forum

Several Pulsar Wind Nebulae (PWN) have been detected in the TeV band in the last years. This TeV emission can be fitted with a purely leptonic model making some assumptions on the Infrared backround around the PWN and on the magnetic field that most of the times is far from its equipartition value. We consider the possibility that part of this emission is due to an hadronic component implying the production of 1-100 TeV neutrinos. The IceCube high-energy neutrino telescope has been collecting data since 2006 and so far no neutrino event has been associated with a PWN. We use the non-detection of neutrinos to constrain the hadronic content of PWN independent of the hadronic model parameters. We also estimate the number of neutrino events expected from these sources in Antares and in KM3NeT and derive the constraints on the hadronic contribution to the TeV emission. Both Antares and KM3NeT have better potential than IceCube to detect neutrinos from PWNs as these sources are galactic.

Host: 
Francis Halzen
Speaker: Dafne Guetta ORT Braude College

 

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Room and Building: 
5280 Chamberlin Hall ***Note New Time****

High-energy astrophysical neutrinos, recently discovered by IceCube, are fertile ground to test for the presence of new physics. We can look for it at previously unexplored energies -- from tens of TeV to a few PeV, far beyond the reach of laboratory experiments. Due to cosmological-scale baselines -- Mpc to Gpc -- tiny new-physics effects, otherwise unobservable, could, by accumulation, become detectable. These include neutrino decay, violation of fundamental symmetries, and novel neutrino-neutrino interactions. I will show that the spectral features and flavor composition of neutrinos can reveal the presence and type of new physics. I will give special attention to neutrino decay. Present-day data are already sensitive to some models. More statistics, improvements in detection techniques, and detector upgrades will only enhance the sensitivity.

Host: 
Carlos Arguelles
Speaker: Mauricio Bustamante Center for Cosmology and AstroParticle Physics (CCAPP), The Ohio State University

 

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Room and Building: 
5280 Chamberlin hall
In 1st part of this talk, we will present the design and the operation of the Daya Bay experiment, the latest neutrino oscillation results, reactor neutrino flux measurements and new physics searches which had been initiated after the measurements of theta_13 and delta m^squared measurements. In the 2nd part of this talk, we will present the design of the JUNO experiment and its detector system, its physics potential, and the current R&D activities to fulfill its designed physics goals.

Host: 
Kael Hanson
Speaker: Wei Wang, JUNO Spokesperson Sun Yat-sen Univeristy

 

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Room and Building: 
4274 Chamberlin Hall
Collapse-induced thermonuclear explosion (CITE) may explain core-collapse supernovae (CCSNe). We analyze the neutrino signal in CITE and compare it to the neutrino burst of SN1987A. For strong CCSNe, as SN1987A, CITE predicts a proto-neutron star (PNS) accretion phase lasting up to a few seconds that is cut-off by black hole (BH) formation. The neutrino luminosity can later be revived by accretion disc emission after a dead time of few to few ten seconds. In contrast, the neutrino mechanism for CCSNe predicts a short (< 1sec) PNS accretion phase followed by slowly declining PNS cooling luminosity. We repeat statistical analyses used in the literature to interpret the neutrino mechanism, and apply them to CITE. The first 1-2 sec of the neutrino burst are equally compatible with CITE and with the neutrino mechanism. However, the data hints towards a luminosity drop at t~2-3 sec, in some tension with the neutrino mechanism but naturally attributed to BH formation in CITE. The occurrence of neutrino signal events at 5 sec suggests that, within CITE, accretion disc formed by that time. We perform 2D numerical simulations, showing that CITE may be able to accommodate this disc formation time while reproducing the ejected Ni56 mass and ejecta kinetic energy within factors 2-3 of observations. We estimate the accretion disc neutrino luminosity, finding it on the low side but compatible with data to a factor of 10. Given current uncertainties in disc simulations we conclude that direct BH formation may have occurred in SN1987A.<br>
Host: 
Markus Ahlers
Speaker: Kfir Blum Weizmann Institute

 

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Room and Building: 
4274 Chamberlin Hall

The Tokai to Kamioka (T2K) experiment is a 295-km long-baseline neutrino experiment aimed towards the measurement of neutrino oscillation parameters Theta-13 and Theta 23. Precise measurement of these parameters requires accurate knowledge of neutrino cross sections. We present a flux-averaged double differential measurement of the charged-current cross section on water with zero pions in the final stage using the T2K off-axis near detector, ND280.

Host: 
Vandenbroucke
Speaker: Tianlu Yuan University of Colorado

 

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Room and Building: 
5280 Chamberlin Hall
Dark Matter in the form of Weakly Interacting Massive Particles (WIMPs) is typically expected to induce nuclear recoils in a terrestrial detector target with an annually modulated rate due to the motion of the Earth around the Sun. Although such a modulation has been observed by the DAMA/LIBRA collaboration it is difficult to interpret it as a dark matter signal, given the null results from other experiments.
Experimental anomalies like the annual modulation signal observed in the DAMA/LIBRA project cannot be explained by traditional dark matter scattering on atomic nuclei, but could be accommodated if dark matter scatters predominantly off electrons or if most of the energy is release in the form of photons.
I will present the results of the XENON experiment on leptophilic dark matter searches and we will contrast them with the DAMA signal.
Host: 
Albrecht Karle
Speaker: Mayra Cervantes Purdue University

 

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Room and Building: 
Room 4274
The High Altitude Water Cherenkov (HAWC) Observatory has been fully operational since its inauguration on 20 March 2015. Designed to measure cosmic rays and gamma rays in the very high energy (VHE) range (from 100 GeV to 100 TeV), HAWC observes 2/3 of the entire sky every day. HAWC has a large field of view of ~2 sr and a duty cycle of >95%, making it an ideal instrument to search for both new VHE sources and transient activity in the VHE band. In this talk, I will discuss the results from HAWC's first year of data with the full detector, highlighting several new Galactic sources and demonstrating the capability of HAWC to identify VHE transients. I will also discuss the complementarity between HAWC and other instruments such as IceCube in the context of searching for the sources of the highest energy cosmic rays and neutrinos.
Host: 
Stefan Westerhoff
Speaker: Tom Weisgarber

 

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Room and Building: 
5280 Chamberlin Hall
The CMB community started the planning stages for the "ultimate" ground-based CMB polarization experiment, CMB-S4, in 2013. Since then, the current generation of ground-based experiments has published several detections of B-mode polarization from gravitational lensing, demonstrating the techniques that will be expanded to characterize the signal across the sky. Deep searches for primordial B-mode polarization have shown the challenges in foreground contamination and control of systematics for reaching high sensitivity at large angular scales. The CMB community is currently working on defining the science goals and instrument requirements for CMB-S4. Meanwhile, the next generation of even more powerful CMB polarization experiments will soon begin to produce results. I will give an overview of the current state of the field, and the ongoing planning for CMB-S4.
Host: 
Kam Arnold
Speaker: Darcy Barron University of California, Berkeley

 

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Room and Building: 
5280 Chamberlin
This talk has been rescheduled to occur at the time and located of the Cosmology Journal Club, 12:15-1:15
in 5248 Chamberlin Hall.
Host: 
Peter Timbie
Speaker: David Kaplan UW - Milwaukee

 

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Room and Building: 
5248 Chamberlin Hall

In this talk I'll first review the information that cosmology can provide on neutrino properties, in particular on the sum of neutrino masses. I'll then present constraints on neutrino masses obtained using information from galaxy surveys. In particular, I'll use galaxy power spectrum data from the WiggleZ Dark Energy Survey (WZ) and from the Luminous Red Galaxies (LRG) sample of the Sloan Digital Sky Survey-Data Release 7 (SDSS-DR7). I'll show how the constraints on neutrino masses, obtained using Planck temperature and polarisation measurements, are improved by the information on the full shape of the power spectrum. Adding also Baryon Acoustic Oscillations measurements, the constraints on neutrino masses are further improved, since these measurements help in breaking cosmological parameters degeneracies. The tighter upper limit (0.13 eV) is obtained using SDSS-DR7 LRG together with Baryon Acoustic Oscillations measurements and Planck data. This value is close to the one recently obtained using Lyman-alpha data. Finally, I'll outline the implications of these current bounds for particle physics and the interplay with laboratory experiments, such as tritium beta decay and neutrinoless double-beta decay experiments.

Host: 
Markus Ahlers
Speaker: Viviana Niro Madrid, Autonoma U. & Madrid, IFT

 

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Room and Building: 
4274 Chamberlin Hall

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