Speaker: Tom Hartman (Cornell)
Title: Replica Wormholes and the Information Paradox
Zoom: https://zoom.us/j/186024391
Host: John Terning
Abstract:
Black hole evaporation seems to create too much entropy. This violates unitarity and is the essence of Hawking's black hole information paradox. I will give a broad overview of recent progress on this problem involving spacetime wormholes in the gravitational path integral. This leads to a new calculation of the entropy compatible with unitarity, and has general consequences for how we interpret black holes in quantum gravity.
User:
High-Energy Seminars
Time:
1:30pm - 2:30pm
Send Reminder:
Yes - 0 days 8 hour 0 minutes before start
Description:
Speaker: Ryutaro Matsudo
Title: Missing final state puzzle in the monopole-fermion scattering
Zoom: https://zoom.us/j/186024391
Host: John Terning
Abstract: It has been known that when a charged fermion scatters off a monopole, the fermion in the s-wave component must flip its chirality, i.e., fermion number violation must happen. This fact has led to a puzzle; if there are two or more flavors of massless fermions, any superposition of the fermion states cannot be the final state of the s-wave scattering as it is forbidden by conservation of the electric and flavor charges. The unitary evolution of the state vector, on the other hand, requires some interpretation of the final states. We solve the puzzle by finding new particle excitations in the monopole background, where multi-fermion operators exhibit condensation. The particles are described as excitations of closed-string configurations of the condensates.
Description:
Earth Day
User:
High-Energy Seminars
Time:
1:30pm - 2:30pm
Send Reminder:
Yes - 0 days 8 hour 0 minutes before start
Description:
Speaker: Alexandria Costantino
Title: Breakdown of the Narrow Width Approximation and other Aspects of Timeline Processes in AdS
Zoom: https://zoom.us/j/186024391
Host: Markus Luty
Abstract:
Working in a slice of (4+1)-dimensional AdS truncated by branes, it's well known that the propagator contains a tower of poles which correspond to narrow particles---KK modes. Does this picture of "a tower of narrow modes" hold to arbitrarily high energies when interactions are present? Generically these narrow modes will get a finite width which can grow with KK number, possibly becoming as large as the mass gap between the modes. What happens when these resonances overlap and mix at high energies, and could this have implications for timelike processes? In my talk, I will address these questions and will discuss possible implications for cascade decays of particles at large KK number.
User:
High-Energy Seminars
Time:
4:00pm - 6:00pm
Description:
Long-lived particle searches with the ATLAS detector
The Standard Model has been successful at LHC, with the Higgs discovery in 2012, and very little deviations seen between the observed data and the theory expectation. However, there are still many outstanding questions, which motivate searches for Beyond-the-Standard-Model (BSM) physics. BSM physics can manifest in the LHC collisions in a variety of ways; in many extension of the SM, particles can acquire macroscopic lifetimes, giving rise to novel signatures: decays away from the interaction point, tracks that don't extend into the calorimeters, for example. These provide challenges in terms of reconstruction, triggering, and background estimation. I will discuss how we look for long-lived particles with the ATLAS detector and go into detail in two searches where we either reconstruct the long-lived particle or its decay products. I will also talk about the detector upgrade intended for high-luminosity operation and the impact on long-lived searches with the ATLAS detector.