SEARCH · Engineering Papers

Results for “CP VIOLATION”

Search indexed NASA NTRS and DOE OSTI research on propulsion, heat transfer, battery materials and energy systems. Follow report and document links to the original sources.

SourceResearch connectionFrom yearThrough year

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 361 records · Page 20

All sources NASA NTRS DOE OSTI

DOE OSTI2012

Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons

We present improved measurements of CP-violation parameters in the decays B{sup 0} {yields} {pi}{sup +}{pi}{sup -}, B{sup 0} {yields} K{sup +}{pi}{sup -}, and B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}, and of the branching fractions for B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0} and B{sup 0} {yields} K{sup 0}{pi}{sup 0}. The results are obtained with the full data set collected at the {Upsilon}(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, corresponding to 467 {+-} 5 million B{bar B} pairs. We find the CP-violation parameter values and branching fractions S{sub {pi}{sup +}{pi}{sup -}} = -0.68 {+-} 0.10 {+-} 0.03, C{sub {pi}{sup +}{pi}{sup -}} = -0.25 {+-} 0.08 {+-} 0.02, {Alpha}{sub K{sup -}{pi}{sup +}} = -0.107 {+-} 0.016{sub -0.004}{sup +0.006}, C{sub {pi}{sup 0}{pi}{sup 0}} = -0.43 {+-} 0.26 {+-} 0.05, {Beta}(B{sup 0} {yields} {pi}{sup 0}{pi}{sup 0}) = (1.83 {+-} 0.21 {+-} 0.13) x 10{sup -6}, {Beta}(B{sup 0} {yields} K0{pi}{sup 0}) = (10.1 {+-} 0.6 {+-} 0.4) x 10{sup -6}, where in each case, the first uncertainties are statistical and the second are systematic. We observe CP violation with a significance of 6.7 standard deviations for B{sup 0} {yields} {pi}{sup +}{pi}{sup -} and 6.1 standard deviations for B{sup 0} {yields} K{sup +}{pi}{sup -}, including systematic uncertainties. Constraints on the Unitarity Triangle angle {alpha} are determined from the isospin relations among the B {yields} {pi}{pi} rates and asymmetries. Considering only the solution preferred by the Standard Model, we find {alpha} to be in the range [71{sup o}, 109{sup o}] at the 68% confidence level.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2019

Searches for Electric Dipole Moments—Overview of Status and New Experimental Efforts

Searches for permanent electric dipole moments (EDMs) of fundamental particles, atoms and molecules are promising experiments to constrain and potentially reveal beyond Standard Model (SM) physics. A non-zero EDM is a direct manifestation of time-reversal (T) violation, and, equivalently, violation of the combined operation of charge-conjugation (C) and parity inversion (P). Identifying new sources of CP violation can help to solve fundamental puzzles of the SM, e.g., the observed baryon-asymmetry in the Universe. Theoretical predictions for magnitudes of EDMs in the SM are many orders of magnitude below current experimental limits. However, many theories beyond the SM require larger EDMs. Experimental results, especially when combined in a global analysis, impose strong constraints on CP violating model parameters. Including an overview of EDM searches, I will focus on the future neutron EDM experiment at TRIUMF (Vancouver). For this effort, the TUCAN (TRIUMF Ultra Cold Advanced Neutron source) collaboration is aiming to build a strong, world leading source of ultra cold neutrons (UCN) based on a unique combination of a spallation target and a superfluid helium UCN converter. Another focus will be the search for an EDM of the diamagnetic atom 129 Xe using a 3 He comagnetometer and SQUID detection. The HeXeEDM collaboration has taken EDM data in 2017 and 2018 in the magnetically shielded room (BMSR-2) at PTB Berlin.

71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗

DOE OSTI2013

Final Report for DE-FG02-00ER41145

Research in high energy physics has been conducted under this research contract. The research includes the discovery of CP violation in the decays of B mesons and the determination of the CKM mechanism as the source of all CP violation in hadrons. Searches for physics beyond the standard model has resulted in limits from the B to S gamma transition and the discovery of the intermediate range oscillations of electron neutrinos. This last discovery will enable the discovery of all properties of neutrino mixing in the next round of neutrino experiments.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗

DOE OSTI2022

One-loop matching for quark dipole operators in a gradient-flow scheme

The quark chromoelectric dipole (qCEDM) operator is a CP-violating operator describing, at hadronic energies, beyond-the-standard-model contributions to the electric dipole moment of particles with nonzero spin. In this paper we define renormalized dipole operators in a regularization-independent scheme using the gradient flow, and we perform the matching at one loop in perturbation theory to renormalized operators of the same and lower dimension in the more familiar MS scheme. We also determine the matching coefficients for the quark chromo-magnetic dipole operator (qCMDM), which contributes for example to matrix elements relevant to CP-violating and CP-conserving kaon decays. The calculation provides a basis for future lattice QCD computations of hadronic matrix elements of the qCEDM and qCMDM operators.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2014

Measurements of Direct C P -Violating Asymmetries in Charmless Decays of Bottom Baryons

Here, we report final measurements of direct CP-violating asymmetries in charmless decays of neutral bottom hadrons to pairs of charged hadrons with the upgraded Collider Detector at the Fermilab Tevatron. Using the complete √s = 1.96 TeV proton-antiproton collisions data set, corresponding to 9.3 fb –1 of integrated luminosity, we measure A(Λ 0 b → pπ – ) = +0.06 ± 0.07(stat) ± 0.03(syst) and A(Λ 0 b → pK – ) = –0.10 ± 0.08(stat) ± 0.04(syst), compatible with no asymmetry. In addition we measure the CP-violating asymmetries in B 0 s → K – π + and B 0 → K + π – decays to be A(B 0 s → K – π + ) = +0.22 ± 0.07(stat) ± 0.02(syst) and A(B 0 → K + π – )=–0.083 ± 0.013(stat) ± 0.004(syst), respectively, which are significantly different from zero and consistent with current world averages.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2023

Baryogenesis in a parity solution to the strong CP problem

Abstract Space-time parity can solve the strong CP problem and introduces a spontaneously broken SU(2) R gauge symmetry. We investigate the possibility of baryogenesis from a first-order SU(2) R phase transition similar to electroweak baryogenesis. We consider a model with the minimal Higgs content, for which the strong CP problem is indeed solved without introducing extra symmetry beyond parity. Although the parity symmetry seems to forbid the SU(2) R anomaly of theB−Lsymmetry, the structure of the fermion masses can allow for the SU(2) R sphaleron process to produce non-zeroB−Lasymmetry of Standard Model particles so that the wash out by the SU(2) L sphaleron process is avoided. The setup predicts a new hyper-charged fermion whose mass is correlated with the SU(2) R symmetry breaking scale and hence with the SU(2) R gauge boson mass, and depending on the origin of CP violation, with an electron electric dipole moment. In a setup where CP violation and the first-order phase transition are assisted by a singlet scalar field, the singlet can be searched for at future colliders.

Physics↗

DOE OSTI2016

Hints for Leptonic C P Violation or New Physics?

One of the major unanswered questions in the neutrino sector is the issue of leptonic CP violation. Current global oscillation data shows a mild preference for a large, potentially maximal value for the Dirac CP phase in the neutrino mixing matrix. In this letter, we point out that New Physics in the form of neutral-current like non-standard interactions with real couplings would likely yield a similar conclusion even if CP in the neutrino sector were conserved. Therefore, the claim for a discovery of leptonic CP violation will require a robust ability to test New Physics scenarios.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2015

Dark-matter QCD-axion searches

In the late 20th century, cosmology became a precision science. At the beginning of the next century, the parameters describing how our universe evolved from the Big Bang are generally known to a few percent. One key parameter is the total mass density of the universe. Normal matter constitutes only a small fraction of the total mass density. Observations suggest this additional mass, the dark matter, is cold (that is, moving nonrelativistically in the early universe) and interacts feebly if at all with normal matter and radiation. There’s no known such elementary particle, so the strong presumption is the dark matter consists of particle relics of a new kind left over from the Big Bang. One of the most important questions in science is the nature of this dark matter. One attractive particle dark-matter candidate is the axion. The axion is a hypothetical elementary particle arising in a simple and elegant extension to the standard model of particle physics that nulls otherwise observable CP-violating effects (where CP is the product of charge reversal C and parity inversion P) in quantum chromo dynamics (QCD). A light axion of mass 10 -(6–3) eV (the invisible axion) would couple extraordinarily weakly to normal matter and radiation and would therefore be extremely difficult to detect in the laboratory. But, such an axion is a compelling dark-matter candidate and is therefore a target of a number of searches. Compared with other particle dark-matter candidates, the plausible range of axion dark-matter couplings and masses is narrowly constrained. This focused search range allows for definitive searches, where a nonobservation would seriously impugn the dark-matter QCD-axion hypothesis. Axion searches use a wide range of technologies, and the experiment sensitivities are now reaching likely dark-matter axion couplings and masses. Our paper is a selective overview of the current generation of sensitive axion searches. Finally, not all techniques and experiments are discussed, but I hope to give a sense of the current experimental landscape of the search for dark-matter axions.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Latest Three Flavor Neutrino Oscillation Results from the NOvA Experiment.

NOvA, is a two-detector, long-baseline neutrino oscillation experiment located at Fermilab, Batavia, IL, USA. It is designed primarily to constrain neutrino oscillation parameters such as the atmospheric mass squared splitting, $\Delta m^2_{32}$, the mixing angle, $\theta_{23}$, neutrino mass hierachy, and the CP-violating phase, $\delta_{CP}$, using $\nu_\mu \ (\bar{\nu}_\mu)$ disappearance and $\nu_e \ (\bar{\nu}_e)$ appearance data. NOvA receives a high purity instense beam of neutrinos and anti-neutrinos from Fermilab's Neutrinos at Main Injector (NuMI) beamline. The NOvA near detector (ND) observes un-oscillated $\nu_\mu \ (\bar{\nu}_\mu)$ and beam $\nu_e \ (\bar{\nu}_e)$ events, while the far detector (FD), which is situated 810 km away from the near detector, records un-oscillated $\nu_\mu \ (\bar{\nu}_\mu)$ and oscillated $\nu_e \ (\bar{\nu}_e)$ events. The best fit values of the oscillation parameters are extracted by performing a joint fit of the far detector predicted events to data from $\nu_\mu \to \nu_\mu$, $\bar{\nu}_\mu \to \bar{\nu}_\mu$, $\nu_\mu \to \nu_e$, and $\bar{\nu}_\mu \to \bar{\nu}_e$ oscillation channels. We present latest joint fit results from NOvA based on a neutrino-beam exposure of $27.24 \times 10^{20}$ POT and an anti-neutrino beam exposure of $12.55\times 10^{20}$ POT and improved simulations.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Three-Flavor Neutrino Oscillations at NOvA

NOvA, is a two-detector, long-baseline neutrino oscillation experiment located at Fermilab, Batavia, IL, USA. It is designed primarily to constrain neutrino oscillation parameters such as the atmospheric mass squared splitting, $\Delta m^2_{32}$, the mixing angle, $\theta_{23}$, neutrino mass hierachy, and the CP-violating phase, $\delta_{CP}$, using $\nu_\mu \ (\bar{\nu}_\mu)$ disappearance and $\nu_e \ (\bar{\nu}_e)$ appearance data. NOvA receives a high purity 900 KW instense beam of neutrinos and anti-neutrinos from Fermilab's Neutrinos at Main Injector (NuMI) beamline. NOvA used functionally identical finely granulated liquid scintillation detectors, both situated 14.6 mrad off-axis to the beam direction. The NOvA near detector observes un-oscillated $\nu_\mu \ (\bar{\nu}_\mu)$ and beam $\nu_e \ (\bar{\nu}_e)$ events, while the far detector, which is situated 809 km away from the near detector, records un-oscillated $\nu_\mu \ (\bar{\nu}_\mu)$ and oscillated $\nu_e \ (\bar{\nu}_e)$ events. We will discuss the neutrino oscillation analysis strategy at NOvA and the latest three-flavor oscillation results from 10 years of NOvA data in this talk.

43 PARTICLE ACCELERATORS↗

DOE OSTI2025

NOvA in 10 Minutes

NOvA is a long-baseline neutrino oscillation experiment based at Fermilab, IL, USA, that observes $\nu_\mu \ (\bar{\nu}_\mu) \to \nu_\mu\ (\bar{\nu}_\mu)$ disappearance and $\nu_\mu \ (\bar{\nu}_\mu) \to \nu_e \ (\bar{\nu}_e)$ appearance oscillations from a beam of muon neutrinos (anti-neutrinos) provided by the Fermilab's NuMI beamline. The experiment consists of two functionally identical active liquid scintillattor tracking calorimeters, both situated 14.6 mrad off-axis to the beam direction. The detectors are made out of extruded PVC cells arranged in alternating horizontal and vertical planes for 3-dimensional reconstruction of neutrino events. The NOvA experiment has a wide-ranging scientific program that includes studying standard 3-flavor neutrino oscillations, resolution of neutrino mass orderings, measuring the CP-violating phase, $\delta_{CP}$, beyond standard model (BSM) phenomenon such as non-standard interactions (NSI) and sterile neutrino searches, neutrino-nucleus cross-section measurements, exotics, astrophysics and more. The NOvA experiment leverages its identical detector technology to mitigate systematic uncertainties for its neutrino oscillation analysis. This talk will provide an overview of the experiment's detector design and the data-driven techniques used by the experiment in its neutrino oscillation analysis.

Choudhary, Brajesh [Delhi U.]↗

DOE OSTI2026

Tests of LBNF Beam Monitor Prototypes for the DUNE Experiment

The Deep Underground Neutrino Experiment (DUNE) is a long-baseline on-axis neutrino oscillation experiment that will use a beam from the Long-Baseline Neutrino Facility (LBNF) to constrain the mixing angle $$\theta_{23}$, the neutrino mass hierarchy, and the CP violating phase $\delta_{CP}$. To ensure the beam remains on-axis, the LBNF beamline will employ two ionization chamber systems: the Hadron Alignment Detection System (HADeS) for primary beam alignment and the Muon Monitoring System (MuMS) for continuous beam monitoring and neutrino flux estimation. We have constructed prototypes for these systems at the University of Texas at Austin based on a design currently used in the NuMI hadron monitor. These prototypes were tested with a radioactive source and in beam tests at Fermilab's Irradiation Test Area. We present the results of these studies and discuss ongoing efforts to optimize the HADeS and MuMS designs.

Murthy, Chinmay↗

DOE OSTI2026

Event Selections in the NOvA 2024 Analysis

The NuMI Off-axis $\nu_e$ Experiment (NOvA) is a long-baseline neutrino oscillation experiment that studies a neutrino beam produced by the Neutrinos at the Main Injector (NuMI) facility at Fermilab to constrain the PNFS mixing angles, the neutrino mass hierarchy, and the CP-violating phase $\delta_{CP}$. These parameters are extracted by comparing the spectra of muon neutrinos and electron neutrinos measured at the near and far detectors, using an extrapolation of the Near Detector spectra. Accurate event selection is critical to this process, as only interactions with well-reconstructed energies and interaction types should be included in the oscillation analysis to reduce systematic uncertainties. In this work, we describe the selection criteria used for muon and electron neutrinos in the Near and Far Detector. We demonstrate the effectiveness of the criteria by examining the efficiency and purity of the event selections as well as their impact on key variables used in the oscillation analysis.

Chen, Hanyi [Indiana U.]↗

DOE OSTI2026

New directions for joint neutrino oscillation measurements with T2K and NOvA

The first joint analysis of data from the NOvA and T2K neutrino oscillations experiments was published in 2025, offering the most precise measurements of the larger mass splitting $\Delta m_{32}^{2}$, the largest mixing angle $\theta_{23}$, and the CP-violating phase $\delta_{CP}$ available at the time. In addition to working towards a reanalysis with additional data collected since that analysis, the collaborations are now exploring possible constraints on BSM physics scenarios. This poster will discuss the potential of a joint measurement of parameters in a framework treating effective non-standard neutral-current neutrino-matter interactions, NC-NSI. Uniquely, the differing baselines and energies of T2K and NOvA allow strong constraints to be set on the electron-muon and electron-tau parameters of NSI contributions to the Hamiltonian, while at the same time maintaining good sensitivity to the standard 3-flavor neutrino oscillations parameters, including the CP phase.

Mikola, Veera [Glasgow U.]↗

DOE OSTI2026

NOvA in 10 Minutes

NOvA is a long-baseline neutrino oscillation experiment that utilizes the NuMI beamline at Fermilab. The experiment consists of two functionally identical, segmented liquid scintillator detectors. A 300-ton near detector sits at Fermilab, while a 14-kiloton far detector is located 810 km away in Ash River, Minnesota. Both are situated 14.6 mrad off the beam axis to peak the neutrino energy spectrum near the first oscillation maximum. NOvA measures muon neutrino disappearance and electron neutrino appearance in both neutrino and antineutrino beam modes, providing sensitivity to the neutrino mass ordering, the octant of the atmospheric mixing angle \theta_{23}, and the CP-violating phase \delta_{CP}. In this talk, I will give a concise overview of the NOvA experiment and its detectors, followed by highlights from recent oscillation analyses. I will also highlight notable cross-section measurements at the near detector. Finally, I will briefly introduce ongoing analyses beyond the standard three-flavor oscillation framework, including searches for sterile neutrinos and non-standard interactions, as well as exotic signatures such as magnetic monopoles, light dark matter, neutrino magnetic moments, and cosmic-ray muon studies.

Khanam, Aklima [Syracuse U. (main)] (ORCID:0009000↗

DOE OSTI2020

Details of the NOvA 3-flavor oscillation analysis

NOvA is a world-leading long-baseline neutrino oscillation experiment. Its fine granularity allows the detection and identification of particle interactions in the detectors, notably muon and electron neutrino interactions. NOvA can measure the electron neutrino and antineutrino appearance rates, as well as the muon neutrino and antineutrino disappearance rates, in order to constrain the neutrino oscillations parameters, the neutrino mass hierarchy and the CP-violating phase $\delta_{CP}$.NOvA's latest results combine both neutrino data (8.85$\times{}10^{20}$ POT) and antineutrino data (12.33$\times{}10^{20}$ POT). A 4.4$\sigma$ evidence for $\overline{\nu}_{e}$ appearance in a $\overline{\nu}_{\mu}$ beam was measured. In addition, NOvA favors the Normal Hierachy (1.9$\sigma$) and prefers the Upper Octant for $\theta_{23}$ (1.6$\sigma$).}

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2024

Latest Three Flavor Neutrino Oscillation Results from the NOvA Experiment.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗

DOE OSTI2020

Probing the top Yukawa coupling at the LHC via associated production of single top and Higgs

We study Higgs boson production associated with single top or anti-top via t-channel weak boson exchange at the LHC. The process is an ideal probe of the top quark Yukawa coupling, because we can measure the relative phase of htt and hWW couplings, thanks to the significant interference between the two amplitudes. By choosing the emitted W momentum along the polar axis in the th ($\bar{t}h$) rest frame, we obtain the helicity amplitudes for all the contributing subprocesses analytically, with possible CP phase of the Yukawa coupling. We study the azimuthal asymmetry between the W emission and the Wb ($\bar{b}$) → t($\bar{t}$) h scattering planes, as well as several t and $\bar{t}$ polarization asymmetries as a signal of CP violating phase in the htt coupling. Both the azimuthal asymmetry and the polarization perpendicular to the scattering plane are found to have the opposite sign between the top and anti-top events. We identify the origin of the sign of asymmetries, and propose the possibility of direct CP violation test in pp collisions by comparing the top and anti-top polarization at the LHC.

72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗