• Brookhaven physicists are using detectors at the Relativistic Heavy Ion Collider to explore how the matter that makes up atomic nuclei behaved just after the Big Bang.

• Brookhaven physicists and engineers are collaborators in the ATLAS experiment at CERN's Large Hadron Collider.

• LBNE and the Daya Bay Neutrino Experiments seek to understand the subtle oscillations of neutrinos, ghost-like particles formed in the heart of stars

• In the LSST and BOSS experiments, Brookhaven physicists seek to measure and constrain the properties of dark matter, dark energy and the standard cosmological model.

### Nuclear Physics

#### PHENIX

Responsibile for the operation and  physics exploitation of the PHENIX experiment at RHIC.

#### STAR

Responsibile for the operation and  physics exploitation of the STAR experiment at RHIC.

#### RHIC Spin

Leads, supports, and provides for the common requirements of the RHIC spin program, particularly for polarimetry.

#### RIKEN BNL Research Center

Conducts quantum chromodynamics and proton spin structure research.

#### Nuclear Theory

The nuclear theory group conducts research in all areas of QCD, including structure of hadrons and nuclei at high energies, the QCD phase diagram and the properties of quark-gluon matter.

#### RHIC Computing Facility

Provides computing services for experiments at RHIC, and the Large Synoptic Survey Telescope project.

### High-Energy Physics

#### Cosmology & Astrophysics

Solving problems in observational cosmology: how to measure and constrain properties of dark matter, dark energy and the standard cosmological model.

#### Electronic Detector

Studies very rare processes at the Intensity Frontier.

#### Omega

Group members are collaborators on the LHC ATLAS experiment.

#### Physics Application

Develops physics applications software for the LHC ATLAS experiment.

#### High-Energy Theory

Focuses on providing theoretical foundation for the search for physics beyond the standard model, including lattice QCD calculations of key quantities required for this quest.

#### ATLAS Computing Facility

Provides computing services for U.S. ATLAS.

### High-Energy Physics

#### Baryonic Oscillation Spectroscopic Survey

BOSS studies dark energy—the force thought to be responsible for the universe’s accelerating expansion.

#### Dark Energy Survey

Seeks to probe the origin of the accelerating universe and uncover the nature of dark energy by measuring the 14-billion-year history of cosmic expansion.

#### Large Synoptic Survey Telescope

A 3.2 gigapixel camera mounted in a  ground-based telescope designed to produce the widest, densest, and most complete images of our universe ever captured.

#### Deep Underground Neutrino Experiment

An international collaboration working to precisely measure neutrino oscillations.

#### ATLAS

An experiment at CERN's Large Hadron Collider designed to detect particles created by proton-proton collisions.

#### Daya Bay Neutrino Experiment

An international collaboration studying the subtle transformations of neutrinos.

#### MicroBooNE

Measures low energy neutrino cross sections and investigates low energy excess events observed by the MiniBooNE experiment.

#### Muon g-2

A high precision measurement of the muon's g-2 value. A deviation between theory and observed value will suggest the existence of new particles.

#### Mu2e

Experiment which directly probes the Intensity Frontier and aids research on the Energy and Cosmic frontiers with precision measurements to characterize properties of new particles.

### Nuclear Physics

#### PHENIX

An experiment at the Relativistic Heavy Ion Collider designed to explore quark gluon plasma.

#### STAR

An experiment at the Relativistic Heavy Ion Collider designed to explore quark gluon plasma.

#### Electron Ion Collider (Future)

Plans for the world's first electron-nucleus collider, also known as eRHIC, call for the addition of a 5 to 10 GeV electron ring inside the RHIC tunnel.

The Physics Department is part of Brookhaven's Nuclear & Particle Physics Directorate.

### Seminars & Colloquia

1. FEB

27

Tuesday

Physics Colloquium

"The Multi-Messenger Picture of a Neutron Star Merger"

Presented by Brian Metzger, Columbia University

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, February 27, 2018, 3:30 pm

Hosted by: Peter Petreczky

On August 17 the LIGO/Virgo gravitational wave observatories detected the first binary neutron star merger event (GW170817), a discovery followed by the most ambitious electromagnetic (EM) follow-up campaign ever conducted. A gamma-ray burst (GRB) of short duration and very low luminosity was discovered by the Fermi and INTEGRAL satellites within 2 seconds of the merger. Within 11 hours, a bright but rapidly-fading thermal optical counterpart was discovered in the galaxy NGC 4993 at a distance of only 40 Mpc. The properties of the optical transient match remarkably well predictions for kilonova emission powered by the radioactive decay of heavy nuclei synthesized in the expanding merger ejecta by the r-process. The rapid spectral evolution of the kilonova emission to near-infrared wavelengths demonstrates that a portion of the ejecta contains heavy lanthanide nuclei. Two weeks after the merger, rising non-thermal X-ray and radio emission were detected from the position of the optical transient, consistent with delayed synchrotron afterglow radiation from an initially off-axis relativistic jet with the properties consistent with those of (on-axis) cosmological short GRB. I will describe a unified scenario for the range of EM counterparts from GW170817 and their implications for the astrophysical origin of the r-process and the properties of neutron stars. I will preview the upcoming era of multi-messenger astronomy, once Advanced LIGO/Virgo reach design sensitivity and a neutron star merger is detected every few weeks.

2. MAR

6

Tuesday

Physics Colloquium

"Quantum simulation of gauge theories in optical lattices"

Presented by Alexei Bazavov, Michigan State University

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, March 6, 2018, 3:30 pm

Hosted by: Andrei Nomerotski

hile non-perturbative approaches such as lattice gauge theory led to significant advances in understanding the physics of strong interactions, many problems remain out of reach for classical computation, in particular, real-time dynamics or properties of QCD at finite baryon density that are being explored in heavy-ion collision experiments. Recent advances in the technology of engineering custom interactions for ultra-cold atomic gases in optical lattices opened a possibility for quantum simulations as was envisioned by R. Feynman in the 1980s. The main idea is that the degrees of freedom of the original system are mapped onto a quantum Hamiltonian whose dynamics can be realized in a laboratory. Many condensed matter Hamiltonians, such as Bose-Hubbard model, have been recently studied in this way. Quantum simulation of gauge theories is however challenging since the gauge symmetry is not naturally present in the ultra-cold atomic systems. I will review the current status of theoretical proposals for quantum simulation of field theories and then focus on our recent work on an explicitly gauge-invariant formulation of the Abelian-Higgs model for simulation on optical lattices.

3. APR

3

Tuesday

Physics Colloquium

"Eigenstate thermalization and its implications to statistical mechanics"

Presented by Anatoli Polkovnikov, Boston University

3:30 pm, Large Seminar Room, Bldg. 510

Tuesday, April 3, 2018, 3:30 pm

Hosted by: Rob Pisarski

In this talk I will overview recent developments in understanding quantum chaos through random matrix theory. I will discuss various conjectures on the nature of quantum stationary states in chaotic systems and show numerical evidence supporting them. It is the random nature of eigenstates, which ultimately leads to loss of information about initial conditions and leads to emergence of statistical mechanics in isolated systems. I will then introduce the so-called Eigenstate Thermalization Hypothesis (ETH) ansatz first proposed by J. Deutsch and M. Srednicki in 90th, which gives a unified framework for the structure of physical observable in quantum chaotic systems. I will demonstrate how the ETH ansatz naturally leads to emergence of various thermodynamic relations. At the end of the talk I will mention some open problems.

1. MAR

2

Friday

Nuclear Theory/RIKEN Seminar

"Quark / Antiquark Correlations in Heavy-Light Ion Collisions"

Presented by Matt Sievert, LANL

2 pm, Small Seminar Room, Bldg. 510

Friday, March 2, 2018, 2:00 pm

Hosted by: Chun Shen

It has long been known that sub-nucleonic fluctuations of the energy density in the initial stages of heavy ion collisions play an important role in generating the observed distributions of particles and their flow. These energy density fluctuations are dominated by the radiation of small-x gluons which are populated to classically large occupation numbers in the wave functions of ultra-relativistic heavy ions. While these soft gluons dominate the initial conditions for the energy density, it is quark production which determines the initial conditions of other conserved charges, like flavor and baryon number. With the recent development of state-of-the art hydrodynamics codes tailored to the Beam Energy Scan which can propagate these conserved charges into the final state, it is timely and important to calculate the initial conditions of these conserved charges from first principles in QCD. In this talk, I will present new results for the spatial correlations among quarks and antiquarks produced at mid-rapidity by pair production from small-x gluons. This single-pair production mechanism, which has been studied for some time in momentum space, is the leading contribution to these correlations in coordinate space for dilute-dense collisions. As one moves from the dilute-dense regime toward the dense-dense regime, correlations due to double pair production become more important, and these correlations persist over larger length scales than the single-pair production mechanism. Over nonperturbative length scales, only the correlations from the overlap geometry remain. I will present explicit results for quark-antiquark correlations due to single pair production, and I will outline some preliminary results for the various double-pair production mechanisms. The ultimate goal of this work will be to construct a code which can initialize these conserved charges over all length scales in heavy-ion collisions.

2. MAR

9

Friday

Nuclear Theory/RIKEN Seminar

"TBA"

Presented by Anna Stasto, Penn State

2 pm, Small Seminar Room, Bldg. 510

Friday, March 9, 2018, 2:00 pm

Hosted by: Chun Shen

3. MAR

20

Tuesday

Nuclear Physics Seminar

"Probing the collectivity of heavy quarks in pPb collisions with prompt D0 elliptic flow using CMS detector"

Presented by Zhenyu Chen, Rice University

11 am, Small Seminar Room, Bldg. 510

Tuesday, March 20, 2018, 11:00 am

Hosted by: Lijuan Ruan

Recent years, evidence for collective effects has been revealed in pp and pPb collisions when looking at events releasing large number of particles. The experimental observations lead to a debate of the formation of strongly coupled Quark-Gluon Plasma in those small collision systems. Azimuthal anisotropy coefficient (vn) of heavy-flavor particles, and especially the comparison to light flavor particles vn, can shed light on the strength of the coupling between heavy flavor quarks and the hypothesized hydrodynamic medium at a significantly reduces size, and impose further constrains on different interpretations related to the origin of the observed collectivity. In this talk, the most recent results of prompt D0 meson elliptic flow (v2) in high-multiplicity pPb collisions are presented over a wide transverse momentum range. The results are compared to those of strange hadrons, including Kshort, Lambda, Cascade and Omega particles.

4. APR

6

Friday

Nuclear Theory/RIKEN Seminar

"TBA"

Presented by Andreas Schmitt, University of Southampton

2 pm, Small Seminar Room, Bldg. 510

Friday, April 6, 2018, 2:00 pm

Hosted by: Chun Shen

5. MAY

25

Friday

Nuclear Theory/RIKEN Seminar

"TBA"

Presented by Stanley Brodsky, Standford Univeristy

2 pm, Small Seminar Room, Bldg. 510

Friday, May 25, 2018, 2:00 pm

1. MAR

6

Tuesday

Instrumentation Division Seminar

"Table-top MeV laser particle accelerator @ kHz repetition rate"

Presented by Enam Chowdhury, Department of Physics, Ohio State University

2:30 pm, Large Conference Room, Bldg. 535

Tuesday, March 6, 2018, 2:30 pm

At the Extreme Light Lab at the Air Force Research Laboratory, Dayton, we explore light matter interaction at relativistic fields with liquid targets. Although demonstrations of up to 4 GeV1 electrons and ~100 MeV protons2 have been achieved in the past, all of these are not feasible as future accelerators, due to their slow duty cycle (usually single shot, rarely 1 Hz). There are many challenges to increasing the duty cycle, where laser technology, target technology, damage to system, target alignment, high repetition rate sub-micron plasma diagnostics provides nearly insurmountable obstacles. In this program, we developed ways to accelerate MeV x-rays, electrons3 and ions4 at kHz repetition rate with a small milli-joule class laser system, by developing a combination of suitable laser system, diagnostic system, target system and experimental data collection system capable of handling the high duty cycle. We also perform femtosecond-time resolution pump-probe imaging of the interaction, and extensive large scale relativistic laser plasma interaction simulations5 that reveal the nature of the acceleration processes. Such a system opens the door to extensive future application as a source for materials processing, radiation hardness testing, medical isotope production, time resolved proton probing on relativistic interactions, and many others.

2. MAR

8

Thursday

Particle Physics Seminar

"New neutrino oscillation results from NOvA"

Presented by Jeremy Wolcott, Tufts University

3 pm, Small Seminar Room, Bldg. 510

Thursday, March 8, 2018, 3:00 pm

Hosted by: Chao Zhang

The NOvA experiment is an off-axis long-baseline neutrino oscillation experiment using the NuMI $\nu_{\mu}$ beam originating at Fermilab. By examining the disappearance of muon neutrinos and the appearance of electron neutrinos between the near detector at Fermilab and the far detector in Ash River, MN, NOvA has the potential to help answer a number of fundamental questions: Are the neutrinos' masses ordered the same way as those of the charged leptons? Do leptons experience charge-parity violation? Are there underlying symmetries in the way the neutrino states mix with one another? In this talk I will present NOvA's most recent constraints on the answers to those questions utilizing muon neutrino disappearance and electron neutrino appearance. These updated results are based on a 50% increase in exposure relative to previous results as well as numerous simulation and analysis improvements.

3. MAR

15

Thursday

Particle Physics Seminar

"Precision Measurements of Asymmetries and Spectra in Neutron Decay"

Presented by Brad Plaster, University of Kentucky

3 pm, Small Seminar Room, Bldg. 510

Thursday, March 15, 2018, 3:00 pm

Hosted by: Chao Zhang

Precision measurements of various asymmetries in neutron decay permit an extraction of the weak axial-vector coupling constant, gA, a fundamental quantity important for weak-interaction physics and as a benchmark for lattice QCD calculations. I will discuss a recent new result from the UCNA Experiment at Los Alamos National Laboratory for a 0.16% precision result on gA from a measurement of the 'A' asymmetry, which represents the parity-violating angular correlation between the neutron's spin and the decay electron's momentum. This long-standing effort was carried out with a superconducting solenoidal electron spectrometer at the LANL Ultracold Neutron (UCN) facility. This new result will be placed in the context of historical results for gA and recent discrepant values for the neutron lifetime obtained via different experimental techniques. I will also discuss the first-ever extraction of the Fierz interference term 'b' in free neutron decay from an analysis of the electron's spectral shape as measured in the UCNA Experiment. A non-zero 'b' term would result from beyond-Standard Model interactions, such as Scalar or Tensor physics. Although the result for 'b' from the UCNA Experiment was systematics limited, it points to the requisite significant improvements in the characterization of the detector energy response that future experiments aimed at a measurement of 'b' will need to achieve in order to probe beyond Standard Model physics at a competitive precision.

4. JUL

9

Monday

Office of Educational Programs Event

"High School Research Program Begins"

8 am, Berkner Hall Auditorium

Monday, July 9, 2018, 8:00 am

Hosted by: Aleida Perez