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Nuclear and Particle Physics Colloquia

Mondays ~ Refreshments 3:30pm Talk: 4:00pm ~ Kolker Room, 26-414

 

Committee:
Jesse Thaler, Chair ~ Daniel Harlow ~ Kerstin Perez ~Philip Harris

 

Colloquia Archives

 

September 11, 2017

hosted by: Will Detmold

Cynthia Keppel, Jefferson Laboratory

Nuclear Physics in Proton Radiotherapy

Abstract: Discoveries and technological advances spurred by the demands of nuclear and particle physics research find applications in many disciplines, including providing benefit to society through the treatment and diagnosis of disease. As an example, proton radiation therapy is a precise form of radiation treatment for cancer. Due to the characteristic Bragg peak associated with ion energy deposition, proton therapy provides the radiation oncologist an improved method of treatment localization within a patient, as compared with conventional radiation therapy using X-rays. This can be accomplished only in concert with concurrent advances in tumor identification and localization, patient motion and positioning, treatment planning and evaluation, and a host of supporting technologies. An overview of hadron, in particular proton, therapy will be presented, with an emphasis on landmark and recent technological developments spurred by nuclear science.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)



September 18, 2017

hosted by: Kerstin Perez

William Wester, Fermi National Accelerator Laboratory

Search for Axion Dark Matter

Abstract: The axion is a proposed particle whose existence might account for much of the dark matter of the universe. This same particle also arises as the solution to the strong-CP problem of particle physics. There have several decades of experiments that have attempted to detect new particles with many of the properties of the axion - but without being sensitive to the preferred region of parameter space. I will report on the Axion Dark Matter Experiment, ADMX, which is currently running and achieving the required sensitivity towards potential discovery.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)

 

 



September 25, 2017

hosted by:  Mike Williams


Tim Gershon, Univeristy of Warwick

LHCb highlights and future prospects

Abstract: The LHCb experiment at CERN has proved spectacularly that precision measurements in heavy quark flavour physics can be made with data collected in high-energy proton proton collisions. Among its achievements are the first observation of the rare Bs -> mu+mu- decay, the most precise measurements of CP violation parameters in B and D mixing and decays, and numerous ground-breaking developments in spectroscopy including the first observations of pentaquark states.  I will recap the key features of the experiment that enabled this level of performance, and discuss what future improvements need to be made in order to capitalise on the much larger data samples that will become available in the HL-LHC era.

 

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)



October 2, 2017

hosted by:Janet Conrad


Tatsuya Kikawa, TRIUMF

Lee Grodzins Postdoctoral Award Winner

Quest for new CP violation by neutrino oscillation and neutron EDM measurement

Abstract: CP violation is an important signal to understand the mechanism how the mater-antimatter asymmetry has been evolved in our universe. I have searched for the new CP violation beyond the standard model by the neutrino oscillation measurement in the T2K experiment and the neutron electric dipole moment measurement at TRIUMF. 


T2K is a long-baseline neutrino experiment in which a muon neutrino beam produced by J-PARC is sent 295 km across Japan to Super-Kamiokande, to study neutrino oscillations. If CP violation occurs in neutrinos, it will manifest itself as a difference in the oscillation probabilities of neutrinos and antineutrinos. Thus, the precise measurement of the neutrino oscillation is a good probe to search for the new CP violation. 


Measurement of electric dipole moment (EDM) of a fundamental particle is also a good probe to search for the new CP violation since a non-zero EDM indicates the CP violation. Ultracold neutrons (UCN) are very low energy neutrons ( 300 neV), which are reflected on material surface. They are the ideal tool to study the neutron EDM since they can be confined in an EDM measurement cell for a long time. At TRIUMF, UCN are produced by accelerator driven spallation neutrons and superfluid helium UCN source for the precise neutron EDM measurement.

 

In this seminar, I will report the present status and the future prospect of the CP violation searches by these experiments and my original and unique contributions.

 

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)



October 9, 2017



NO TALK: COLUMBUS DAY HOLIDAY

 



October 16, 2017

hosted by: Bolek Wyslouch

Rebecca Surman, University of Notre Dame

Forging the heaviest elements

Abstract: The origin of the heaviest elements has long been one of the greatest mysteries of nuclear astrophysics. The only known means to synthesize nuclei up to uranium and thorium is rapid neutron capture, or r-process, nucleosynthesis, and exactly where and how the r-process occurs has remained uncertain for decades. Recently disparate lines of evidence---from astronomical observations, modeling of galactic chemical evolution and individual astrophysical events, neutrino and nuclear experiment and theory, and gravitational wave detections---appear to be converging on a preferred site of production: neutron star mergers. Here we will review the available evidence and discuss the role nuclear physics can play in a definitive resolution to this mystery. 

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)



October 23, 2017

hosted by: Tracy Slatyer

Tomer Valansky, TAU and IAS

New Directions in the Search for Dark Matter

Abstract: The existence of dark matter has been well established with overwhelming evidence, but its particle identity is still unknown. For more than three decades, significant theoretical and experimental efforts have been directed towards the search for a Weakly Interacting Massive Particle (WIMP), often overlooking other possibilities. The lack of an unambiguous positive WIMP signal, at both indirect- and direct-detection experiments and at the LHC, stresses the need to expand dark matter research into additional theoretical scenarios and, more importantly, to develop new experimental capabilities that go beyond the limitations of WIMP detection. In this talk I will shortly review the current status of the field and discuss new theoretical ideas and experimental avenues for searching for light dark matter in the MeV to GeV mass range, focusing on direct detection experiments.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)



October 30, 2017

hosted by: Jesse Thaler


Yuval Grossman, Cornell University

Polarization

Abstract: Determining polarization of particles is an important tool to probe Dirac structures of couplings. I will discuss several ways to probe polarization in cases where the traditional methods do not work. In particular, I will show how we can measure b-quark polarization in high energy processes and hoe to probe photon polarization in radiative Higgs decays.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)



November 6, 2017

hosted by:Daniel Harlow


Tom Faulkner, University of Illinois

Bounding negative energy density with causality and quantum information

Abstract: Negative energy density can arise naturally in Quantum Field Theory. However too much of it can lead to pathological spacetimes when coupling the theory to gravity. In this talk I will discuss conjectured bounds on negative energy density and sketch very recent general proofs of these bounds. The methods we use combine causality considerations with concepts taken from quantum information theory.


time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)

 



November 13, 2017

hosted by: Kerstin Perez

Regina Caputo, University of Maryland/NASA/GSFC

Dark Matters: The Search for the Universe's Missing Mass 

Abstract: The era of precision cosmology revealed that 80% of the matter in the universe is non-luminous, or dark. The nature of dark matter is crucial to our understanding of the structure and evolution of the universe after the big bang. One promising dark matter candidate, motivated by both particle- and astrophysics, is the Weakly Interacting Massive Particle (WIMP). The detection of this elusive particle requires a multi-pronged approach. I will present results from searches for WIMPs using high-energy gamma-rays from the Fermi Gamma-Ray Space Telescope. I will also discuss complementary detection techniques and their necessity for dark matter discovery. Although no WIMP has yet been found, I will discuss what is ruled out so far, current ongoing searches, and our best prospects for finding the source of the universe's missing mass.


time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.

 



November 20, 2017

hosted by: Stanley Kowalski

David Armstrong, The College of William & Mary

Precision Measurement of the Proton’s Weak Charge     

Abstract: The QWeak collaboration has used parity-violating elastic electron-proton scattering at very low momentum transfer to precisely measure the proton's weak charge. The weak charge is cleanly predicted within the Standard Model, with minimal theoretical uncertainty. 
Thus, this measurement provides an avenue for a sensitive search for beyond-the-Standard Model (BSM) physics. The final results for the weak charge will be presented, as well as the extracted values of the vector weak couplings of the up and down quarks, and the weak mixing angle. We will also discuss implications for BSM physics at the multi-TeV energy scale.

 


time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.



November 27, 2017

hosted by: Markus Klute


Spencer J. Gessner, CERN

Advances in Beam-Driven Plasma Wakefield Acceleration

Abstract:Plasma wakefield accelerators have been used to accelerate particles by tens of GeV in less than a meter of plasma. A simple extrapolation implies that we should be able to reach the TeV-scale in less than 100 meters. So what’s stopping us? In this talk, I’ll describe recent advances in the field of beam-driven plasma wakefield acceleration (PWFA) and discuss the challenges we face trying to turn PWFA research into PWFA technology.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)

 


December 4, 2017

hosted by: Bill Barletta


Daniel Ratner, SLAC

Cooling High Energy Hadrons Using the Microbunching Instability and Shot Noise Suppression

Abstract:Electron and stochastic cooling are proven methods for cooling low energy hadron beams, but at present there is no way of cooling hadrons at the 100 GeV scale. To increase the cooling rate, Derbenev and Litvinenko proposed Coherent electron Cooling (CeC), which makes use of the large bandwidth of a Free Electron Laser to amplify the hadron signal. This talk describes an alternative CeC scheme using the microbunching instability as the amplifier. I will also describe a method for suppressing shot noise fluctuations in the electron beam current to further improve cooling rates.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


December 11, 2017

hosted by: Richard Milner


Daniel Winklehner, MIT

Development and Applications of High Intensity Ion Beams using Cyclotrons

Abstract: In the field of the physics of particle beams we are constantly pushing the frontiers of highest energy, highest intensity, and best quality beams. These are strongly correlated parameters and often increasing one comes at the expense of reducing the others. However, through innovation and by leveraging physics (e.g. collective effects) we continuously reduce these tradeoffs. Recently, we have developed a very compact and comparably cheap cyclotron-based driver to produce very high intensity beams. The system will be able to deliver continuous wave (cw) electrical beam currents of >10 mA of protons on target in the energy regime around 60 MeV. This is a factor 4 higher than the current state-of-the-art for cyclotrons. All areas of physics and energy science that call for high cw currents can greatly benefit from this result. In this colloquium, I will mainly focus on one example use of this accelerator for producing flavor-pure neutrino beams. I will present the beam physics challenges that I have addressed to bring us to the present state and outline the next steps that will boost the energy to 1 GeV and enable multi-megawatt cyclotrons for neutrino physics and accelerator driven systems.

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)


December 18, 2017

hosted by:Lindley Winslow


Suzanne Sheehy, University of Oxford

TBA

Abstract: TBA

time:    4:00 p.m.
place:   Kolker Room (26-414)

(refreshments at 3:30 p.m.)