August 2015  

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SEP
3
Thursday
RIKEN Lunch Seminar
"Analytic solution of the Boltzmann equation in the early universe"
Presented by Jorge Noronha, University of Sao Paulo
12:30 pm, Building 510 Room 2160
Thursday, September 3, 2015, 12:30 pm
Hosted by: Daniel Pitonyak
A general method for exactly computing the nonlinear collision term of the Boltzmann equation for a massless relativistic gas in a homogeneous and isotropic spacetime is presented. This approach is used to find an exact analytical solution of the nonlinear relativistic Boltzmann equation in a FriedmannRobertsonWalker spacetime. This solution can be used to investigate analytically the interplay between global expansion and local thermalization in rapidly evolving systems.
SEP
4
Friday
Nuclear Theory/RIKEN Seminar
"Asymptotic freedom of gluons in the Fock space"
Presented by Stanislaw Glazek, University of Warsaw
2 pm, Small Seminar Room, Bldg. 510
Friday, September 4, 2015, 2:00 pm
Hosted by: Soeren Schlichting
Asymptotic freedom of gluons is defined in terms of scaledependent renormalized QCD Hamiltonian operators that act in the Fock space. These operators are calculable in a new way [1,2], by solving a doublecommutator differential equation [3], where the derivative is with respect to a scale parameter defined within the renormalization group procedure for effective particles (RGPEP). The RGPEP equation and its solutions are invariant with respect to boosts and may serve as a tool in attempts to dynamically explain the parton and constituent models of hadrons in QCD. The thirdorder QCD solution of the RGPEP equation to be discussed [2], provides an explicit example of how asymptotic freedom of gluons is exhibited in the scaledependence of Hamiltonians as operators in the Fock space. This example also prepares ground for the fourthorder calculations of effective strong interactions using the same RGPEP equation [3], to facilitate Hamiltonian studies of many stronginteraction processes, e.g., those that involve heavy quarkonia in relativistic motion. Applications to other sectors of the Standard Model than the strong interactions await development, while only preliminary results are currently available in the domain of precise calculations in QED[4]. [1] Dynamics of effective gluons, S. D. Glazek, Phys. Rev. D63, 116006, 29p (2001). [2] Asymptotic freedom in the frontform Hamiltonian for gluons, M. GomezRocha, S. D. Glazek, arXiv:1505.06688 [hepph], to appear in Phys. Rev. D. [3] Perturbative formulae for relativistic interactions of effective particles, S. D. Glazek, Acta Phys. Pol. B43, 1843, 20p (2012). [4] Calculation of size for boundstate constituent
SEP
8
Tuesday
Chemistry Department Seminar
""Tracking atoms and charges in metal catalysts under reaction conditions"
Presented by Anatoly I. Frenkel, Physics Dept, Yeshiva University, NY
10 am, Room 300, 3rd Floor, Chemistry Bldg. 555
Tuesday, September 8, 2015, 10:00 am
Hosted by: Alex Harris
In the last decade, complexity of catalytic nanoparticles attracted much attention as a major factor in catalytic processes. Atomic and electronic structure and dynamics of particles, as well as their interactions with support and adsorbates, are important descriptors of their catalytic activity. The main challenge is how to investigate these factors in a working catalyst, at high temperature and pressure, and how to do so without breaking the correlations between components of this complex system. I will give a brief overview of new methods developed recently to enable such combined studies under realistic reaction conditions. Our approach is to single out electronic charge of metal atoms in a cluster as an "observable" quantity and develop methods to "observe" it experimentally under realistic reaction conditions, and model theoretically. In this framework, complex interactions between metal and adsorbates, metal and support, and support and adsorbates can be all accounted for in terms of their effects on the cluster charge. I will review recent results utilizing this approach for a prototypical catalyst, 1nm Pt nanoparticles supported on silica. Using high energy resolution methods of Xray absorption and emission spectroscopies (HERFD and RIXS), as well as in situ IR spectroscopy (DRIFTS) and electron microscopy, aided with firstprinciples (DFT) modeling, we deduced that the structure of atoms and charges in the catalyst is strongly heterogeneous and that it changes dynamically with the change in temperature and pressure of adsorbates (H2 or CO).
SEP
8
Tuesday
Joint Nuclear Physics and Particle Physics Seminar
"Understanding the nature of neutrinos via neutrinoless doublebeta decay"
Presented by Wenqin Xu, Los Alamos National Laboratory
11 am, Small Seminar Room, Bldg. 510
Tuesday, September 8, 2015, 11:00 am
Hosted by: Jin Huang
Neutrinos provide a critical portal to physics beyond the Standard Model, yet the nature of neutrinos is largely unknown, including the neutrino mass hierarcy and if neutrinos are Majorana particles. Majorana particles are fermions that are their own antiparticles. Neutrinos being Majorana particles would explicitly violate lepton number conservation, and would pave the way to understand the matterantimatter asymmetry in the universe. Neutrinoless doublebeta (0) decay is a hypothesized process where two neutrons decay into two protons and two electrons simultaneously without emitting neutrinos. It is possible only if neutrinos are Majorana particles, and it is the only feasible way to experimentally establish the Majorana or Dirac nature of neutrinos. The observation of 0 decay would also provide complementary information related to neutrino masses. After decades of experimental eorts, the next generation 0 decay experiments will have a signicant discovery potential to observe 0 decay, if neutrinos are indeed Majorana particles. In this talk, we will discuss the physics of neutrinoless double beta decay and review the experiments searching for it. We will focus on the Majorana Demonstrator, a 40kg modular Germanium detector array, which searches for 0 decay in 76Ge and aims at demonstrating a path forward to next generation 0 decay experiments.
SEP
9
Wednesday
Hospitality Coffee & Playgroup Event
"Hospitality Coffee & Playgroup (10amnoon)"
10 am, Recreation Hall, Bldg. 317
Wednesday, September 9, 2015, 10:00 am
Play group will sometimes schedule different types of play dates at various venues. To see the schedule and join, please use https://www.facebook.com/groups/241354149387588/#!/groups/241354149387588/ and open 'BNL Spouses and Kids' and sign in. You do need an established Facebook account in order to do so.
SEP
16
Wednesday
Hospitality Coffee & Playgroup Event
"Hospitality Coffee & Playgroup (10amnoon)"
10 am, Recreation Hall, Bldg. 317
Wednesday, September 16, 2015, 10:00 am
Play group will sometimes schedule different types of play dates at various venues. To see the schedule and join, please use https://www.facebook.com/groups/241354149387588/#!/groups/241354149387588/ and open 'BNL Spouses and Kids' and sign in. You do need an established Facebook account in order to do so.
SEP
19
Saturday
BNL Team at the Port Jeff Dragon Boat Race Festival
"BERA APAA Event"
9 am, Port Jefferson Harborfront Park
Saturday, September 19, 2015, 9:00 am
The BERA Asian Pacific American Association (APAA) is inviting all members of the Brookhaven Lab community to join them at the the 2015 Port Jefferson Dragon Boat Race Festival on Sept. 19 to cheer the BNL Team. This is the festival's second year, and teams from all over the New York tristate area will be competing. The BERA/BNL Team is practicing all summer for this race. Come cheer us on! View the event's official web site at http://portjeffdragonracefest.com/
SEP
23
Wednesday
Hospitality Coffee & Playgroup Event
"Hospitality Coffee & Playgroup (10amnoon)"
10 am, Recreation Hall, Bldg. 317
Wednesday, September 23, 2015, 10:00 am
Play group will sometimes schedule different types of play dates at various venues. To see the schedule and join, please use https://www.facebook.com/groups/241354149387588/#!/groups/241354149387588/ and open 'BNL Spouses and Kids' and sign in. You do need an established Facebook account in order to do so.
SEP
30
Wednesday
Hospitality Coffee & Playgroup Event
"Hospitality Coffee & Playgroup (10amnoon)"
10 am, Recreation Hall, Bldg. 317
Wednesday, September 30, 2015, 10:00 am
Play group will sometimes schedule different types of play dates at various venues. To see the schedule and join, please use https://www.facebook.com/groups/241354149387588/#!/groups/241354149387588/ and open 'BNL Spouses and Kids' and sign in. You do need an established Facebook account in order to do so.
SEP
30
Wednesday
BSA Distinguished Lecture
"A hundred years of visualizing molecular structure"
Presented by Professor Venki Ramakrishnan, MRC Laboratory of Molecular Biology in Cambridge, England, United Kingdom
4 pm, Berkner Hall Auditorium
Wednesday, September 30, 2015, 4:00 pm
Hosted by: Peter Wanderer
It has been a hundred years since molecules were first visualized directly by using xray crystallography. That technique gave us our first look at molecules as simple as common salt to one as complex as the ribosome that has almost a million atoms. In the last few years, electron microscopy has offered an alternative to directly obtaining the structure of very large molecules. I will describe some highlights in this journey with an emphasis on the recent developments in electron microscopy and how it is creating a new range of possibilities for visualizing biological structures.
OCT
1
Thursday
Particle Physics Seminar
"Top Quark Precision Physics and the Fate of the Universe"
Presented by Andreas Jung, Purdue University
3 pm, Small Seminar Room, Bldg. 510
Thursday, October 1, 2015, 3:00 pm
Hosted by: Ketevi A. Assamagan
The talk will discuss recent measurements in the top quark sector, the heaviest known elementary particle known so far, performed at the Fermilab Tevatron Collider and at the LHC. I will highlight Tevatron results that are competitive to those at the LHC, especially regarding the top quark mass and production asymmetry. The talk will also present CMS results on the top quark mass and Yukawa coupling. I will discuss the implications for the standard model electroweak sector regarding the vacuum stability. I will conclude with an outlook towards the high luminosity phase of the LHC and the CMS silicon detector upgrades required for the high luminosity phase.
OCT
2
Friday
CFN Colloquium
"Insitu XAS, TXM and RIXS experiments"
Presented by Frank de Groot, Debye Institute of Nanomaterials Science, Utrecht University, Netherlands
11 am, Bldg 735, Seminar Room, 2nd Floor
Friday, October 2, 2015, 11:00 am
Hosted by: Deyu Lu
New developments in insitu xray absorption (XAS), transmission xray microscopy (TXM) and resonant inelastic xray scattering (RIXS) will be discussed. A brief introduction is given of xray absorption spectroscopy, including the multiplet interpretation of XAS spectral shapes [1,2]. Nanoscale chemical imaging of catalysts under working conditions is possible with transmission xray microscopy. We have shown that TXM can image a catalytic system under relevant reaction conditions and provides detailed information on the morphology and composition of the catalyst material in situ [3]. The 20 nanometer resolution combined with powerful chemical speciation by XAS and the ability to image materials under reaction conditions opens up new opportunities to study many chemical processes. I will discuss the present status of insitu TXM, with an emphasis on the abilities of the 10+ nm resolution TXM technique in comparison with 0.1 nm STEMEELS [4,5]. Hard Xray TXM allows the measurement of chemical images and tomographs under more realistic conditions, using a capillary reactor at 10 bar FischerTropsch conditions [6]. The second part of the talk deals with resonant inelastic xray scattering (RIXS), In 2p3d RIXS one scans through the 2p XAS edge and measures the optical excitation range. As an example, the RIXS spectra of CoO will be discussed. The experimental resolution of 100 meV at ADRESS allows the detailed observation of the electronic structure. Firstprinciple theoretical modelling was performed for the ground state and multiplet analysis for the RIXS experiments. The implications for measurements on coordination compounds (cobalt carboxylates) and cobalt nanoparticles is discussed, in particular the comparison with optical spectroscopy [7]. Related to the RIXS measurements is the analysis of Fluorescence yield (FY) detected xray absorption spectra (XAS), including the intrinsic deviations of the FYXAS spectral shape from
OCT
7
Wednesday
BSA Distinguished Lecture
"Universe or Multiverse?"
Presented by Andre Linde, Stanford University
4 pm, Berkner Hall Auditorium
Wednesday, October 7, 2015, 4:00 pm
Hosted by: Peter Wanderer
Cosmological observations show that the universe is very uniform on the maximally large scale accessible to our telescopes. The best theoretical explanation of this uniformity is provided by the inflationary theory. Andrei Linde will briefly describe the status of this theory in view of recent observational data. Rather paradoxically, this theory predicts that on an extremely large scales, much greater than what we can see now, the world may look totally different. Instead of being a single spherically symmetric balloon, our universe may look like a "multiverse," a collection of many different exponentially large balloons ("universes") with different laws of lowenergy physics operating in each of them. The new cosmological paradigm, supported by developments in string theory, changes the standard views on the origin and the global structure of the universe and on our own place in the world.
NOV
6
Friday
Nuclear Theory/RIKEN Seminar
"Linearly resummed hydrodynamics from gravity"
Presented by Yanyan Bu, Ben Gurion University of the Negev
2 pm, Small Seminar Room, Bldg. 510
Friday, November 6, 2015, 2:00 pm
Hosted by: Soeren Schlichting
Using fluid/gravity correspondence, we study allorder resummed hydrodynamics in a weakly curved spacetime. The underlying microscopic theory is a finite temperature \mathcal{N}=4 superYangMills theory at strong coupling. To linear order in the amplitude of hydrodynamic variables and metric perturbations, the fluid's stressenergy tensor is computed with derivatives of both the fluid velocity and background metric resummed to all orders. In addition to two viscosity functions, we find four curvature induced structures coupled to the fluid via new transport coefficient functions, which were referred to as gravitational susceptibilities of the fluid (GSF). We analytically compute these coefficients in the hydrodynamic limit, and then numerically up to large values of momenta. We extensively discuss the meaning of all order hydrodynamics by expressing it in terms of the memory function formalism, which is also suitable for practical simulations. We also consider GaussBonnet correction in the dual gravity, which is equivalent to some 1/N corrections in the dual CFT. To leading order in the GaussBonnet coupling, we find that the memory function is still vanishing.
DEC
17
Thursday
Particle Physics Seminar
"Search for Higgs Bosons produced in association with top quarks with the ATLAS detector"
Presented by Professor Vivek Jain, SUNY Albany
3 pm, Small Seminar Room, Bldg. 510
Thursday, December 17, 2015, 3:00 pm
Hosted by: Ketevi Assamagan
Due to the large measured mass of the top quark, the Yukawa coupling of the top quark (yt) is much stronger than that of other quarks. The observation of the tÂ¯tH production mode would allow for a direct measurement of this coupling, to which other Higgs production modes are only sensitive via loop effects. Since yt is expected to be close to unity, it is also argued to be the quantity that might give insight into the scale of new physics. Using various Higgs decay modes, we report on the status of this search using data collected with the ATLAS detector at 7 and 8 TeV collision energies.