Abstract: Mu2e will operate with an unprecedentedly high intensity muon beam. During planned calibration runs (with \mu^+ rather than \mu^-) the experiment will collect on the order of 10^12 stopped muons. I will discuss a new proposal to search for BSM particles with masses below the muon and pion mass which result in a monoenergetic positron that can be observed in the Mu2e tracker.
Abstract: The Deep Underground Neutrino Experiment (DUNE) will be the leading next-generation particle project in the US. It aims to measure CP violation in the neutrino sector and determine the mass ordering of neutrinos. These measurements are straightforward conceptually but challenging practically. One outstanding issue is the modeling of GeV neutrino-nucleus interaction. With a lack of a proper theoretical framework, it is not only difficult to simulate neutrino events in the detector accurately but also difficult to assess its impact on the physics measurements. I will discuss our attempts at understanding how cross-section uncertainties impact oscillation measurements and new physics searches.
Abstract: The Deep Underground Neutrino Experiment (DUNE) will be the leading next-generation particle project in the US. It aims to measure CP violation in the neutrino sector and determine the mass ordering of neutrinos. These measurements are straightforward conceptually but challenging practically. One outstanding issue is the modeling of GeV neutrino-nucleus interaction. With a lack of a proper theoretical framework, it is not only difficult to simulate neutrino events in the detector accurately but also difficult to assess its impact on the physics measurements. I will discuss our attempts at understanding how cross-section uncertainties impact oscillation measurements and new physics searches.
The strong suppression of bottomonia in ultrarelativistic heavy-ion collisions is a smoking gun for the production of a deconfined quark-gluon plasma (QGP). In this talk, I will discuss recent work that aims to provide a more comprehensive and systematic understanding of bottomonium dynamics in the QGP. The new paradigm is based on an open quantum system approach applied in the framework of the potential non-relativistic QCD EFT (pNRQCD), which has recently been extended to next-to-leading order in the binding energy over temperature. I demonstrate that the computation of bottomonium suppression can be reduced to solving a Lindblad-type equation for the evolution of the b-bbar reduced density matrix including both singlet and octet states and transitions between them. To solve the resulting Lindblad equation, we make use of a quantum trajectories algorithm which can be deployed in a massively parallel manner. Our computation depends on two fundamental transport coefficients that have been evaluated independently using lattice QCD. Comparisons with experimental data for bottomonium suppression and elliptic flow show very good agreement between theory and experiment.
Understanding the physics that governs the valence region of the nucleon is one of the central goals of hadronic physics. The valence region, which is ‘free’ from sea effects, stands as a challenging yet clean testing ground for various theoretical models that attempt to explain physics that operates this regime. Data from various complementary world wide efforts have recently provided tight constraints on PDFs in previously unmeasured regions at a wide range of Bjorken-x and Q2 for quarks, and anti-quarks.
Recently, three Jefferson Lab experiments, MARATHON (Hall A using 3H and 3He targets), BoNUS12 (Hall B using H and D targets), and F2d/F2p (Hall C using H and D targets) finished data taking in which they measured unpo- larized DIS cross sections. MARATHON and BONUS12 used novel techniques in minimizing nuclear effects in extracting the PDFs and their data will help constrain d(x)/u(x) ratio in the high-x region. Also, a planned experiment that proposes to use parity violation (PVDIS on the proton) using the proposed SoLID spectrometer will independently constrain the d(x)/u(x) ratio at high-x without contamination from nuclear corrections.
Recently, the SeaQuest experiment at Fermilab and RHIC at BNL used Drell-Yan dilepton production and W+/W− ratios to constrain the d(x)/u(x) ratio in the intermediate and ‘high-x’ region for sea quarks. Absolute Drell-Yan cross section data taken on a deuterium target at SeaQuest could also be used to constrain the d(x) + u(x) in the high-x region.
For the spin sector, An1 and dn2 experiments (Hall C using 3He target and a polarized e− beam) at Jefferson Lab successfully finished data taking. These experiments along with measurements on the proton from CLAS12 and SoLID will provide data on spin structure functions g1 and g2 for both, the proton and neutron, which will be used for flavor decomposition of u and d helicity distributions in the valence region. Overview of the experimental efforts and recent results will be presented in this talk.
Semi-inclusive deep-inelastic scattering (SIDIS) is an essential tool to probe the quark-gluon structure of the proton and thus for our understanding of non-perturbative QCD dynamics. The CLAS12 experiment has been taking physics data at the upgraded Continuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Laboratory since 2018. It takes advantage of the world record luminosities provided by CEBAF to perform an ambitious program of 3D imaging of the proton in momentum and position space. This talk will present the first results from the SIDIS program. I will focus on the first observation of beam-spin asymmetries in di-pion production in SIDIS. From the measured di-pion correlations a first extraction of the collinear twist-3 PDF e(x), which is sensitive to quark-gluon correlations in the proton, can be performed. Furthermore spin-orbit correlations in the hadronization of longitudinal polarized quarks into pions can be studied for the first time.
Laser spectroscopy of simple atoms is sensitive to properties of the atomic
nucleus, such as its charge and magnetization distribution, or its
polarizability. This allows determining the nuclear parameters from atomic
spectroscopy, but also limits the attainable precision for the determination of
fundamental constants or the test of QED and the Standard Model.
In light muonic atoms and ions, one negative muon replaces all atomic electrons,
resulting in a calculable hydrogen-like system. Due to the muon's large mass
(200 times the electron mass), the muon orbits the nucleus on a 200 times
smaller Bohr radius, increasing the sensitivity of muonic atoms to nuclear
properties by 200^3 = 10 million.
This has resulted in a 10fold increase in the precision of the charge radius of
the proton, deuteron, and the stable helium nuclei. The consequences for atomic
and nuclear physics, the determination of fundamental constants, and the test of
QED and the Standard Model are discussed.
https://www.dropbox.com/sh/69sdbudfg8245pj/AACTb2WyBF_R2ujBHJkIx6zja?dl=0
Many models of neutrino-nucleus scattering are guided by data taken during the 1970's and 1980's by the Argonne, Brookhaven, and Fermilab bubble-chamber experiments, which have limited data sample sizes and large systematic uncertainties. The long-baseline neutrino facility (LBNF) will provide a neutrino beam, primarily composed of $\nu_\mu$ when it runs with forward horn current, and $\bar\nu_\mu$ when it runs with reverse horn current. The beam intensity is driven by the power of the proton beam on the target, which is slated to start at 1.2 MW and will be upgraded to 2.4 MW. The near detectors currently being designed are optimized for DUNE's determination of the neutrino mass ordering and the measurement of $\delta_{\rm{CP}}$. This powerful beam provides unprecedented opportunities to measure the cross sections of neutrinos on protons and neutrons via hydrogen/deuterium targets with integrated particle detection capability. Options range from using the hydrogen in the scintillating plastic in the SAND near detector component, to adding hydrogen-rich gas to the high-pressure gas TPC near detector component, to building a H$_2$/D$_2$ bubble chamber in a separate hall upstream of the DUNE near detector hall. Polarized targets are also under consideration, though these will necessarily involve other elements along with the hydrogen and deuterium, but they will allow the first measurements of neutrino scattering on polarized nuclei.
https://www.dropbox.com/sh/z67mq9zfdwm6wj8/AAC2v83jGvFJOujFrVi2Nmr2a?dl=0
