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All sourcesNASA NTRSDOE OSTI
DOE OSTI2017

Review of lattice results concerning low-energy particle physics: Flavour Lattice Averaging Group (FLAG)

We review lattice results related to pion, kaon, D- and B-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor f + (0), arising in the semileptonic K → π transition at zero momentum transfer, as well as the decay constant ratio f K /f π and its consequences for the CKM matrix elements V us and V ud . Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of SU(2) L × SU(2) R and SU(3) L × SU(3) R Chiral Perturbation Theory. We review the determination of the B K parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. The latter quantities are an addition compared to the previous review. For the heavy-quark sector, we provide results for m c and m b (also new compared to the previous review), as well as those for D- and B-meson-decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. Finally, we review the status of lattice determinations of the strong coupling constant α s .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

FLAG Review 2019: Flavour Lattice Averaging Group (FLAG)

Abstract We review lattice results related to pion, kaon, D -meson, B -meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor $$f_+(0)$$ f + ( 0 ) arising in the semileptonic $$K \rightarrow \pi $$ K → π transition at zero momentum transfer, as well as the decay constant ratio $$f_K/f_\pi $$ f K / f π and its consequences for the CKM matrix elements $$V_{us}$$ V us and $$V_{ud}$$ V ud . Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of $$SU(2)_L\times SU(2)_R$$ S U ( 2 ) L × S U ( 2 ) R and $$SU(3)_L\times SU(3)_R$$ S U ( 3 ) L × S U ( 3 ) R Chiral Perturbation Theory. We review the determination of the $$B_K$$ B K parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for $$m_c$$ m c and $$m_b$$ m b as well as those for D - and B -meson decay constants, form factors, and mixing parameters. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant $$\alpha _s$$ α s . Finally, in this review we have added a new section reviewing results for nucleon matrix elements of the axial, scalar and tensor bilinears, both isovector and flavor diagonal.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2021

Bulk observables at 5.02 TeV using quasiparticle anisotropic hydrodynamics

Abstract We compare predictions of 3+1D quasiparticle anisotropic hydrodynamics (aHydroQP) for a large set of bulk observables with experimental data collected in 5.02 TeV Pb–Pb collisions. We make predictions for identified hadron spectra, identified hadron average transverse momentum, charged particle multiplicity as a function of pseudorapidity, the kaon-to-pion ( $$K/\pi $$ K / π ) and proton-to-pion ( $$p/\pi $$ p / π ) ratios, identified particle and charged particle elliptic flow, and HBT radii. We compare to data collected by the ALICE collaboration in 5.02 TeV Pb–Pb collisions. We find that, based on available data, these bulk observables are well described by aHydroQP with an assumed initial central temperature of $$T_0=630$$ T 0 = 630 MeV at $$\tau _0 = 0.25$$ τ 0 = 0.25 fm/c and a constant specific shear viscosity of $$\eta /s=0.159$$ η / s = 0.159 , which corresponds to a peak specific bulk viscosity of $$\zeta /s = 0.048$$ ζ / s = 0.048 . In particular, we find that the momentum dependence of the kaon-to-pion ( $$K/\pi $$ K / π ) and proton-to-pion ( $$p/\pi $$ p / π ) ratios reported recently by the ALICE collaboration are extremely well described by aHydroQP in the 0–5% centrality class.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
DOE OSTI2022

FLAG Review 2021

Abstract We review lattice results related to pion, kaon, D -meson, B -meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More specifically, we report on the determination of the light-quark masses, the form factor $$f_+(0)$$ f + ( 0 ) arising in the semileptonic $$K \rightarrow \pi $$ K → π transition at zero momentum transfer, as well as the decay constant ratio $$f_K/f_\pi $$ f K / f π and its consequences for the CKM matrix elements $$V_{us}$$ V us and $$V_{ud}$$ V ud . Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of $$SU(2)_L\times SU(2)_R$$ S U ( 2 ) L × S U ( 2 ) R and $$SU(3)_L\times SU(3)_R$$ S U ( 3 ) L × S U ( 3 ) R Chiral Perturbation Theory. We review the determination of the $$B_K$$ B K parameter of neutral kaon mixing as well as the additional four B parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for $$m_c$$ m c and $$m_b$$ m b as well as those for the decay constants, form factors, and mixing parameters of charmed and bottom mesons and baryons. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant $$\alpha _s$$ α s . We consider nucleon matrix elements, and review the determinations of the axial, scalar and tensor bilinears, both isovector and flavor diagonal. Finally, in this review we have added a new section reviewing determinations of scale-setting quantities.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Light meson parton distribution functions from basis light-front quantization and QCD evolution

Here, we investigate the parton distribution functions (PDFs) of the pion and kaon from the eigenstates of a light-front effective Hamiltonian in the constituent quark-antiquark representation suitable for low-momentum scale applications. By taking these scales as the only free parameters, the valence quark distribution functions of the pion, after QCD evolving, are consistent with the E615 experiment at Fermilab. In addition, the ratio of the up quark distribution in the kaon to that in the pion also agrees with the NA3 experimental result at CERN.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2013

Project X: Accelerator Reference Design

Project X is a high-intensity proton facility being developed to support a world-leading program of Intensity Frontier physics over the next two decades at Fermilab. Project X is an integral part of the U.S. Intensity Frontier Roadmap as described in the P5 report of May 2008 [1] and within the Fermilab Strategic Plan of November 2011 [2]. This document represents Part I of the “Project X Book” describing the Project X accelerator facility and the broad range of physics research opportunities enabled by Project X. Parts II and III provide in-depth descriptions of the physics research program, both within and beyond particle physics [3]. The primary elements of the U.S. program to be supported by Project X include: Neutrino Experiments: Experimental studies of neutrino oscillations and neutrino interaction physics with ultra-intense neutrino beams provided by a high-power proton source with energies up to 120 GeV, utilizing near detectors at the Fermilab site and massive detectors at distant underground laboratories. Goal: At least 2 MW of proton beam power at any energy between 60 to 120 GeV; several hundred kW of proton beam power on target at 8 GeV. Kaon, Muon, Nucleon, and Neutron Precision Experiments: World-leading experiments studying ultra-rare kaon decays, searching for muon-to-electron conversion and nuclear electron dipole moments (EDMs), and exploring neutron properties at very high precision. Goal: MW-class proton beams supporting multiple experiments at 1 and 3 GeV, with flexible capability for providing distinct beam formats to concurrent users while allowing simultaneous operations with the neutrino program. Material Science and Nuclear Energy Applications: High-intensity accelerator, spallation, target and transmutation technology demonstrations will provide critical input into the design of future energy systems, including next generation fission reactors, nuclear waste transmutation systems and future thorium fuel-cycle power systems. Possible applications of muon spin rotation techniques provide sensitive probes of the magnetic structure of materials. Goal: Provide MW-class proton beams at 1 GeV, coupled with novel targets required to support a broad range of materials science and energy applications. Platform for Evolution to Future Frontier Facilities: A high-intensity proton source will strengthen and modernize the Fermilab injector complex, providing a robust platform upon which to build future frontier facilities. The Neutrino Factory and Muon Collider are examples that would provide world-leading capabilities at the Intensity and Energy Frontiers for many decades to come. Goal: Provide a straightforward upgrade path for a 4 MW, low-duty-factor source of protons at energies between 5 and 15 GeV. These four elements are expected to form the basis of the Mission Need statement required for the Department of Energy (DOE) Critical Decision 0 (CD-0), and represent the fundamental design criteria for Project X. The following chapters present the Reference Design for the Project X accelerator facility. The Reference Design is based on a continuous wave (CW) superconducting (SC) linac providing up to 1 and 3 MW of beam power at 1 and 3 GeV respectively. A pulsed linac provides acceleration of roughly 4% of the beam delivered from the CW linac to the 8 GeV injection energy of the existing Recycler/Main Injector complex. Upgrades to the Recycler and Main Injector support a factor of three increase, beyond current capabilities, in proton beam power at 60 to 120 GeV. The Reference Design represents a facility that will be unique in the world with unmatched capabilities for the delivery of very high beam power, with flexible beam formats, to multiple users at multiple energies. The utilization of linacs within the Project X facility enables capabilities beyond what is achievable with circular accelerators. It is anticipated that the final configuration and operating parameters of the complex will be further refined through the R&D program in advance of CD-2.

Holmes, Stephen D.↗
DOE OSTI2015

Search for Time Reversal Symmetry Violation with TREK at J-PARC (Closeout Report)

This DOE Early Career Award has enabled Dr. Michael Kohl to take on and expand his leadership roles in several projects such as TREK@J-PARC, OLYMPUS@DESY, MUSE@PSI, and in the experimental program in Hall C at Jefferson Lab. Dr. Kohl has successfully accomplished several items: (i) Preliminary results from SANE (E08-003) at Jefferson Lab: Former HU graduate student Anusha Liyanage has pursued her PhD research on SANE. Her analysis of the elastic ep scattering data has resulted in the extraction of the proton electric-to-magnetic form factor ratio from double spin asymmetries at the highest momentum transfer to date. The results are almost final and a publication is in preparation. (ii) Approval of TREK/E36 for running, preparation of simulation and analysis: the TREK experiment has been stage-II approved in fall 2013, has been mounted on the hall floor from November 2014 to April 2015, has been commissioned in April-June 2015 and is scheduled to run in fall 2015. The group has contributed significantly with simulations and magnetic field map calculations, has investigated the sensitivity of TREK to new light neutral particles, and contributed substantially to the mounting and commissioning of the experiment. (iii) Running of OLYMPUS and analysis: Under Dr. Kohl's leadership as spokesman, the OLYMPUS experiment has completed data taking beginning of 2013; calibrations and analysis have been well underway, with results to be expected in the course of 2015. (iv) Operation of GEM detectors at OLYMPUS and MUSE: The GEM telescopes built for OLYMPUS luminosity monitoring with forward-angle ep elastic scattering have been operated successfully, have meanwhile been relocated to PSI, and have been re-commissioned as beam particle trackers for the PSI secondary beams for MUSE. (v) Trained and prepared postdocs and graduate students for their future careers. Two postdocs from Dr. Kohl's group (Dr. Juergen Diefenbach and Dr. Peter Monaghan) have found permanent academic positions. Two former graduate students of the group have graduated and received their PhD degrees in nuclear physics (Dr. Anusha Liyanage and Dr. Ozgur Ates). In particular, this award has enabled Dr. Kohl to pursue the TREK project (Time Reversal Experiment with Kaons) at J-PARC, which he has been leading and advancing as International Spokesperson. Originally proposed as a search for time reversal symmetry violation, the project has evolved into a precision test of lepton flavor universality in the Standard Model along with sensitive searches for physics beyond the Standard Model through a possible discovery of new particles such as a sterile neutrino or a neutral gauge boson from the hidden sector in the mass region up to 300 MeV/c2. Experiment TREK/E36, first proposed in 2010, has been mounted between November 2014 and April 2015, and commissioning with beam has been started in April 2015, with production running anticipated in early summer and late fall 2015. It uses the apparatus from the previous KEK/E-246 experiment with partial upgrades to measure the ratio of decay widths of leptonic two-body decays of the charged kaon to µν and eν, respectively, which is highly sensitive to the ratio of electromagnetic charged lepton couplings and possible new physics processes that could differentiate between μ and e, hence breaking lepton flavor universality of the Standard Model. Through the searches for neutral massive particles, TREK/E36 can severely constrain any new physics scenarios designed to explain the proton radius puzzle.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

An updated estimate of the Mu2e experiment sensitivity

The Mu2e experiment at Fermilab will search for the conversion of a negative muon into an electron inside the field of a nucleus. This process does not conserve charged-lepton flavour and is heavily suppressed in the Standard Model (SM), with a branching ratio < 10-50. Any evidence of it would be an undeniable evidence of new physics beyond the SM. The project sets out to achieve a single event sensitivity of $\sim 3 × 10^{-17}$ on the ratio between the probability for a conversion of a negative muon into an electron and the one for a muon capture by the nucleus. Such a sensitivity would represent a 4 orders of magnitude improvement on the previous upper limit for the process, making possible to test predictions of different extensions of the SM. Mu2e uses three superconducting solenoids to produce and measure the muon conversions. In the first solenoid, the Production Solenoid, pions and kaons are produced, together with other secondary products, by 8 GeV kinetic energy proton interactions in a tungsten target. A gradient magnetic field is specifically designed to direct low momentum particles into the Transport Solenoid, an S-shaped magnet that filters out particles with unwanted charge and momentum. Muons, produced by pion and kaon decays, finally reach the aluminum Stopping Target in the Detector Solenoid, where they eventually stop and convert. The result of the conversion process is a monochromatic electron of ~105 MeV/c momentum. The Detector Solenoid also hosts the two main detectors: a straw tube tracker and two CsI calorimeter disks, both providing measurement of event kinematics. A germanium detector and a LaBr crystal are located downstream of the Detector Solenoid to measure the X and gamma rays produced by the muon captures in the Stopping Target. A veto system of scintillators covering the Detector Solenoid and half of the Transport Solenoid is used to identify and reject cosmic rays interactions. With respect to the initial project, the Mu2e running plan has evolved to a staged configuration with 2 years at reduced intensity before the 2025 accelerator shutdown for the neutrino beam upgrade and 2 or 3 years at full intensity after that. This, together with geometry changes and a better knowledge of detector performances obtained by the first slice tests, has required a full revision of the signal over background selection that is the subject of this thesis. In order to achieve a new estimate of Mu2e sensitivity, the simulation of the data corresponding to the first 2 years of data acquisition has been performed. This includes both conversion electrons (CE) and the main sources of background: cosmics, decay-in orbits (DIO), radiative pion captures (RPC) and antiprotons. The characteristics of the signal and of the main backgrounds have been studied to define the best selection variables for CE. A special effort has been devoted to the evaluation of the antiproton background. The lack of experimental data for antiproton production cross section makes the systematic uncertainty on this background significant. A new parameterization of the cross section has been developed to fit the existing data and to provide a more reliable estimate of the systematic uncertainty by comparing the results of the old and the new model. A special effort has been devoted to the optimization of the antiprotons Monte Carlo generator. This study has also revealed that the dominant component within this background is represented by antiprotons produced in the opposite direction with respect to the Transport Solenoid entrance and then redirected to it by back-scattering processes in the Production Target. This ultimately highlights the sensitivity of the background estimate to the G4 handling of antiproton interactions in the 1 to 3 GeV/c momentum range. Finally, the final experimental sensitivity has been studied. The momentum and time selection have been optimized to obtain the 5-sigma discovery reach or, in case of no signal, the upper limit on conversion probability. The results confirm that, in the firs t two years of data taking, Mu2e will be able to improve the current experimental sensitivity for muon-to-electron conversion in an atomic field by more than 3 order of magnitudes.

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2013

High-Resolution Hypernuclear Spectroscopy at JLab Hall A. Results and perspectives

Hypernuclear spectroscopy via electromagnetic induced reactions is a valuable and powerful way to study hypernuclei, hadronic systems with non-zero strangeness content, providing an alternative to the hadron induced reactions mainly studied so far. Electron-induced hypernuclear spectroscopy has been studied in Hall A at Je!erson Lab [1] on three nuclei, 12C, 16O, and 9Be with unprecedented resolution and with an improved particle identification system, using a RICH detector, in order to unambiguously identify kaons, thus allowing the measurement of high-quality, almost backgroundfree, hypernuclear spectra. Two superconducting septum magnets were added to the existing apparatus in order to permit particle detection at very forward angle providing a reasonable counting rate. These studies have provided the first quantitative information on core-excited states in hypernuclei. In the case of oxygen, a waterfall target has been employed allowing for the simultaneous measurement of hypernuclear production on oxygen and of elementary kaon-? electro-production on protons: a crucial measurement to disentangle the contribution of the elementary reaction from the measured hypernuclear production cross section, yielding direct access to the nucleus-hypernucleus transition structure. A ? binding energy value for 16 ?N calibrated against the elementary (e, e?K+) reaction on hydrogen, has been obtained. Final results for 12C, 16O, 9Be will be presented [1-3]. Results of Hall C experiments will be presented in another talk in this Conference. Since it is essential for further theoretical study of hypernuclei to collect enough information about L production on nucleons and about excitation spectra of a wide variety of ? hypernuclei, a continuation of the successful hypernuclear program at JLab is very desirable. For these reasons Hall A and Hall C Jefferson Lab hypernuclear collaborations decided to merge and propose a new layout for the 12 GeV Jefferson Lab era that has the advantages of both the experimental setups. In fact the new experimental design not only widens and deepens the physics range but also dramatically improves production yield and efficiency allowing to study both mass spectroscopy on a wide range of nuclei (from few body to 208Pb) and pion decay spectroscopy at the same time [4]. Figs.1, 2 show the results obtained for 12C and 16O. Fig. 3 shows the new layout.

Garibaldi, Franco↗
DOE OSTI2023

Electroweak box diagrams on the lattice for pion and neutron decay

CKM matrix is unitary by construction in the standard model(SM). The recent analyses on the first row of CKM matrix show ≈3σ tension with unitarity. Nonperturbative calculations of the radiative corrections can reduce the theory uncertainty in CKM matrix elements. Here we compute the electroweak box contribution to the pion and kaon β decays using seven Nf = 2 + 1 + 1 HISQ-Clover lattice with various pion mass and lattice spacing. The continuum and chiral limit is taken using the leading dependence on M π and a, where M π extrapolation is taken to the physical pion mass and SU(3) symmetric mass for pion and kaon box contribution, respectively. Our results are $\square^{VA}_{γW}|_{π}$ = 2.820(28) × 10 –3 and $\square^{VA}_{γW}|_{K}$ = 2.384(17) × 10 –3 .

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2025

Extracting the distribution amplitude of light pseudoscalar mesons using the HOPE method

The pseudoscalar meson light-cone distribution amplitudes (LCDAs) are essential non-perturbative inputs for a range of high-energy exclusive processes in quantum chromodynamics. In this proceedings, progress towards a determination of the low Mellin moments of the pion and kaon LCDAs by the HOPE Collaboration is reported.

Chang, Alex [National Yang Ming Chiao Tung Univers↗
NASA NTRS1985

Empirical description of the hadron-hadron and hadron-nucleus interaction at the accelerator energy range

Taking into account several assumptions, a formula is transformed into two expressions for kaon and baryon plus antibaryon production in proton interaction and for pion production in pion interactions. Combining both formulae, expression are obtained for the spectrum of kaons and baryons plus antibaryons produced in the meson interactions. For analysis of the cosmic ray propagation in the atmosphere in actual fact, instead of the formulae for interactions of protons and mesons with protons, formulae appropriate for interactions with air nuclei was used. Using the method outlined among others by Elias et al. (1980) simple corrections were introduced to the derived expressions to account for the fact that the target is an air nucleus.

Kubiak, G.↗
NASA NTRS1985

Energy spectra of high energy atmospheric neutrinos

Focusing on high energy neutrinos ( or = 1 TeV), a new calculation of atmospheric neutrino intensities was carried out taking into account EMC effects observed in P-A collisions by accelerator, recent measurement of primary cosmic ray spectrum and results of cosmic ray muon spectrum and charge ratio. Other features of the present calculation are (1) taking into account kinematics of three body decays of kaons and charm particles in diffusion equations and (2) taking into account energy dependence of kaon production.

Mitsui, K.↗
DOE OSTI2018

First Measurement of Monoenergetic Muon Neutrino Charged Current Interactions

aWe report the first measurement of monoenergetic muon neutrino charged current interactions. The NuMI beam absorber provides an intense source of 236 MeV muon neutrino events originating from kaon decay at rest ($K^+\rightarrow \mu^+\nu_\mu$) that are observed by the MiniBooNE detector. The kaon-decay-at-rest (KDAR) neutrino represents a standard candle for studying neutrino-nucleus interactions, cross sections, and energy reconstruction in the hundreds of MeV region and can be used for a number of precision measurements. The KDAR signal at MiniBooNE, observed with $3.9\sigma$ significance, is distinguished from $\nu_\mu$ and $\bar{\nu}_\mu$ backgrounds using arrival time and reconstructed muon energy. This result is the first known-energy, weak-interaction-only probe of the nucleus to yield a measurement of neutrino-nucleus energy transfer ($\omega=E_\nu-E_\mu$).

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2020

Photon induced $K\Lambda $ production on the proton at $E_{\gamma} < 3$ GeV

The associated photoproduction of $K\Lambda$ from the proton for $E_{\gamma} < 3$ GeV is studied using an isobar model in which the non-resonant contributions corresponding to $s$, $t$, $u$ channel diagrams are obtained from a non-linear sigma model with chiral SU(3) symmetry. The model also predicts a contact term and its coupling strength in a natural way to preserve gauge symmetry. The parameters used are the pion decay constant $f_{\pi}$, vector and axial vector current couplings of the baryon octet in terms of the symmetric and antisymmetric couplings $D$ and $F$. In the non-resonant sector, the model is almost parameter free except a common cut-off parameter $\Lambda_{B}$, to describe the hadronic form factors at the strong kaon-nucleon-hyperon($KN\Lambda$) vertices. In the resonance sector, contribution from the various nucleon resonances($R$) in the $s$ channel, hyperon resonances($Y^{*}$) in the $u$ channel, and the kaon resonances($K^{*}$ and $K_{1}$) in the $t$ channel, which are present in the PDG having spin $\le \frac{3}{2}$ and mass $<2$ GeV with significant branching ratio in $K\Lambda$ decay mode have been considered. In the case of the nucleon resonances($R$), the couplings $\gamma NR$ at the electromagnetic vertices are determined in terms of the helicity amplitudes and the $RK\Lambda$ couplings at the strong vertices are determined by the partial decay width of the resonances($R$) decaying to $K\Lambda$. The strong and the electromagnetic couplings of $u$ and $t$ channel resonances are fitted to reproduce the experimental data of CLAS and SAPHIR. The numerical results are presented for the total and differential scattering cross sections and are compared with the available experimental data from CLAS and SAPHIR as well as with some of the recent theoretical models.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
DOE OSTI2013

Exclusive Meson Production in Hall C at JLab 12 GeV

Exclusive meson production plays an important role in probing the quark and gluon distributions in hadrons. The additional flavor degree of freedom in the H(e,e'K^+)Lambda/Sigma^0 reactions provides a unique opportunity to study the mechanism underlying strangeness production and the transition from hadronic to partonic degrees of freedom. The 12-GeV upgrade at Jefferson Lab provides the energies, and Hall~C, with its heavily-shielded detector setup in a highly-focusing spectrometer, is optimal for precision kaon cross section measurements. A new threshold aerogel Cerenkov detection system provides a simple and economical option for kaon identification. Measurements of reactions with neutral final states allow one to probe universal features of the Generalized Parton Distribution and to verify their formalism in thus far unexplored regimes. The addition of a neutral particle spectrometer in Hall C augments its scientific capabilities to include photon detection from, e.g., ?0 decay or Deeply Virtual Compton Scattering. In this talk I will present the current status and discuss the outlook on future studies of probing quark and gluon distributions through exclusive reactions in Hall C as well as the particle identification requirements for each of these stages.

Horn, Tanja↗
DOE OSTI2023

Search for Low mass Higgs Portal Scalars at the MicroBooNE Detector in the NuMI Beam

The MicroBooNE experiment exploits Liquid Argon Time Projection Chamber (LArTPC) technology to detect neutrinos from two beams at Fermilab, Chicago: on-axis Booster Neutrino Beam (BNB) and the off-axis Neutrinos at the Main Injector (NuMI) beam. While the aim of the experiment is to study the low-energy excess of electron neutrino events observed by the MiniBooNE experiment, to search for eV-scale sterile neutrinos and to characterise neutrino interactions on argon, it could also be exploited to probe Beyond Standard Model (BSM) Physics. This thesis presents a BSM search for low-mass Higgs Portal Scalars at MicroBooNE in the NuMI beam using data collected during the Run 1 and Run 3 data-taking periods with a total exposure corresponding to $7.01 \times 10^{20}$ protons on target (POT). The Higgs Portal Model is an extension to the Standard Model in which a dark-sector scalar, $S$, mixes with the Higgs boson with mixing angle $\theta$ and acquires a coupling to the Standard Model fermions via the Higgs Yukawa coupling. We search for low-mass Higgs Portal scalars, in the mass range $100-200$ MeV, at MicroBooNE via the production channel $K \rightarrow \pi + S$, where scalars are produced from kaons decaying at rest in the NuMI target and beam dump, as well as kaons decaying in flight in the decay pipe of the NuMI beam. In the MicroBooNE detector, we search for the decay channel $S \rightarrow e^+e^-$, which is the only decay channel available to the scalars in the mass range of our search. The results are expressed as limits, at the 95\% confidence level, on the scalar-Higgs mixing angle $\theta$ for scalars in the mass range $100-200$ MeV.Date of Award1 Aug 2023Original languageEnglishAwarding InstitutionThe University of ManchesterSupervisorStefan Soldner-Rembold (Supervisor) & Justin Evans (Supervisor)

46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND ↗
DOE OSTI2023

A Search for Heavy Neutral Leptons Decaying to Electron-Positron Pairs and Neutral Pions in the MicroBooNE Detector

This thesis presents a search for heavy neutral leptons (HNLs) decaying inside the MicroBooNE detector. The MicroBooNE detector is a liquid-argon time projection chamber located at Fermilab that receives flux from two neutrino beams; the booster neutrino beam (BNB) and the neutrinos at the main injector (NuMI) beam. The search uses data taken when the NuMI beam was on, with a total exposure of $7.01\times10^{20}$ protons on target. HNLs would be produced in kaon decays, and the source of HNLs targeted in this search is kaons decaying at rest in the NuMI hadron absorber. The kinematics of the HNLs produced in this way allow their decays to be distinguished from the majority of beam-neutrino interactions and cosmic-ray activity that constitute the background. Two HNL decay channels are studied, $\nu$\ee and \vpi. Boosted decision trees (BDTs) are trained to separate the simulated HNL decays from the expected background events. The BDT score distributions are used to calculate upper limits on the mixing angle \umusq in the mass range $10\le m_{\rm HNL}\le 245$~MeV. This is the first direct search for HNL decays to the \vpi channel, and the limits provide the most stringent constraints on \umusq in the mass range $35<\mhnl<175$~MeV.

43 PARTICLE ACCELERATORS↗