C P -invariance violation at short-baseline experiments in 3 + 1 neutrino scenarios
Not Available
de Gouvêa, André↗
SEARCH · Search NASA
Results for “P INVARIANCE”
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.
Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.
Topological quantum phase transitions in the spin–singlet superconductor with Rashba and Dresselhaus (110) spin–orbit couplings
We examine the topological properties of a spin–singlet superconductor with Rashba and Dresselhaus (110) spin–orbit couplings. We demonstrate that there are several topological invariants in the Bogoliubov–de Gennes (BdG) Hamiltonian by symmetry analysis. In particular, the Pfaffian invariant P for the particle–hole symmetry can be used to demonstrate all the possible phase diagrams of the BdG Hamiltonian. We find that the edge spectrum is either Dirac cone or flat band which supports the emergence of the Majorana fermion in this system. For the Majorana flat bands, an edge index, namely the Pfaffian invariant P(k{sub y}) or the winding number W(k{sub y}), is needed to make them topologically stable. These edge indices can also be used in determining the location of the Majorana flat bands. - Highlights: • Majorana fermion can emerge in the spin–orbit coupled singlet superconductor. • Pfaffian invariant and 1D winding number can be used to identify the nontrivial topological phase where Majorana flat band exists. • All the possible phase diagrams in the spin–orbit coupled singlet superconductor are demonstrated. • Majorana flat band only exists in the y direction in our model. • Majorana flat band has a significant experimental signature in the tunneling conductance measurement.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗
Search for electric dipole moments of light ions in storage rings
The Standard Model (SM) of Particle Physics is not capable to account for the apparent matterantimatter asymmetry of our Universe. Physics beyond the SM is required and is searched for by (i) employing highest energies (e.g., at LHC), and (ii) striving for ultimate precision and sensitivity (e.g., in the search for electric dipole moments (EDMs)). Permanent EDMs of particles violate both time reversal (T) and parity (P) invariance, and are via the CPT-theorem also CP-violating. Finding an EDM would be a strong indication for physics beyond the SM, and pushing upper limits further provides crucial tests for any corresponding theoretical model, e.g., SUSY. Direct searches of proton and deuteron EDMs bear the potential to reach sensitivities beyond 10{sup −29} e cm. For an all-electric proton storage ring, this goal is pursued by the US-based srEDM collaboration [2], while the newly found Julich-based JEDI collaboration [1] is pursuing an approach using a combined electric-magnetic lattice which shall provide access to the EDMs of protons, deuterons, and {sup 3}He ions in the same machine. In addition, JEDI has recently proposed to perform a direct measurement of the proton and/or deuteron EDM at COSY using resonant techniques involving Wien filters.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Inclusive production of the $P_c$ resonances in $p \overline p $ collisions
We present a study of the inclusive production in $p \overline p $ collisions of the pentaquark states $P_c(4440)$ and $P_c(4457)$ with the decay to the $J/\psi p$ final state previously observed by the LHCb experiment. Using a sample of candidates originating from decays of $b$-flavored hadrons, we find an enhancement in the $J/\psi p$ invariant mass distribution consistent with a sum of $P_c(4440)$ and $P_c(4457)$. The significance, with the input parameters set to the LHCb values, is $3.0\sigma$. This is the first confirmatory evidence for these pentaquark states. We measure the ratio $N_{\rm prompt}/N_{\rm nonprompt}=0.05 \pm 0.39$ and set an upper limit of 0.8 at the 95\% credibility level. The ratio of the yield of the $P_c(4312)$ to the sum of $P_c(4440)$ and $P_c(4457)$ is less than 0.6 at the 95\% credibility level. The study is based on $10.4~\rm{fb^{-1}}$ of data collected by the D0 experiment at the Fermilab Tevatron collider.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Studying the $P_c(4450)$ Resonance in $J/\psi $ Photoproduction Off Protons
Here, the LHCb has reported the observation of a resonancelike structure, the $P_c(4450)$, in the $J/\psi $ p invariant masses. In our work, we discuss the feasibility of detecting this structure in $J/\psi $ photoproduction, e.g. in the measurements that have been approved for the experiments in Hall A/C and in Hall B with CLAS12 at JLab. Also the GlueX Collaboration has already reported preliminary results. We take into account the experimental resolution effects, and perform a global fit to world J/psi photoproduction data in order to study the possibility of observing the $P_c(4450)$ signal in future JLab data. We present a first estimate of the upper limit for the branching ratio of the $P_c(4450)$ into the $J/\psi $ p channel, and we study the angular distributions of the differential cross sections. This will shed light on the nature and couplings of the $P_c(4450)$ structure in the future photoproduction experiments.
74 ATOMIC AND MOLECULAR PHYSICS↗
Search for Violations of Lorentz Invariance and C P T Symmetry in B ( s ) 0 Mixing
Violations of CPT symmetry and Lorentz invariance are searched for by studying interference effects in B 0 mixing and in B 0 s mixing. Samples of B 0 → J/ψK 0 S and B 0 s → J/ψK + K – decays are recorded by the LHCb detector in proton-proton collisions at center-of-mass energies of 7 and 8 TeV, corresponding to an integrated luminosity of 3 fb –1 . No periodic variations of the particle-antiparticle mass differences are found, consistent with Lorentz invariance and CPT symmetry. Results are expressed in terms of the standard model extension parameter Δa μ with precisions of O (10 –15 ) and O (10 –14 ) GeV for the B 0 and B 0 s systems, respectively. With no assumption on Lorentz (non)invariance, the CPT -violating parameter z in the B 0 s system is measured for the first time and found to be R e(z) = –0.022 ± 0.033 ± 0.005 and Im (z) = 0.004 ± 0.011 ± 0.002, where the first uncertainties are statistical and the second systematic.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
First observation of γ γ → p p ¯ K + K - and search for exotic baryons in p K systems
The process γ γ → p p ¯ K + K - and its intermediate processes are measured for the first time using a 980 fb - 1 data sample collected with the Belle detector at the KEKB asymmetric-energy e + e - collider. The production of p p ¯ K + K - and a Λ ( 1520 ) 0 ( Λ ¯ ( 1520 ) 0 ) signal in the p K - ( p ¯ K + ) invariant mass spectrum are clearly observed. However, no evidence for an exotic baryon near 1540 MeV / c 2 , denoted as Θ ( 1540 ) 0 ( Θ ¯ ( 1540 ) 0 ) or Θ ( 1540 ) + + ( Θ ( 1540 ) - -- ), is seen in the p K - ( p ¯ K + ) or p K + ( p ¯ K - ) invariant mass spectra. Cross sections for γ γ → p p ¯ K + K - , Λ ( 1520 ) 0 p ¯ K + + c . c . and the products σ ( γ γ → Θ ( 1540 ) 0 p ¯ K + + c . c . ) B ( Θ ( 1540 ) 0 → p K - ) and σ ( γ γ → Θ ( 1540 ) + + p ¯ K - + c . c . ) B ( Θ ( 1540 ) + + → p K + ) are measured. We also determine upper limits on the products of the χ c 0 and χ c 2 two-photon decay widths and their branching fractions to p p ¯ K + K - at the 90% credibility level.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Phenomenological constraints on A N in p ↑ p→πX from Lorentz invariance relations
We present a new analysis of A N in p ↑ p→πX within the collinear twist-3 factorization formalism. We incorporate recently derived Lorentz invariance relations into our calculation and focus on input from the kinematical twist-3 functions, which are weighted integrals of transverse momentum dependent (TMD) functions. In particular, we use the latest extractions of the Sivers and Collins functions with TMD evolution to compute certain terms in A N . Consequently, we are able to constrain the remaining contributions from the lesser known dynamical twist-3 correlators.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
An invariance principle in the theory of stability
Invariance principle in Liapunovs stability theory
INVARIANCE↗
Combining geometric-optical and spectral invariants theories for modeling canopy fluorescence anisotropy
The spectral invariants theory ( p -theory) has received much attention in the field of quantitative remote sensing over the past few decades and has been adopted for modeling of canopy solar-induced chlorophyll fluorescence (SIF). However, the spectral invariant properties (SIP) in simple analytical formulae have not been applied for modeling canopy fluorescence anisotropy primarily because they are parameterized in terms of leaf total scattering, which precludes the differentiation between forward and backward leaf SIF emissions. In this study, we have developed the canopy-SIP SIF model by combining geometric-optical (GO) theory to account for asymmetric leaf SIF forward and backward emissions at the first-order scattering and by modeling multiple scattering based on the p-theory, thus avoiding the dependence on radiative transfer models. The applicability of the model simulations especially over 3D heterogeneous canopies was improved by incorporating canopy structure through multi-angular clumping index, and by modeling single scattering from the four components of the scene in view according to the GO approach. The results show good consistency with both the state-of-the-art SIF models and multi-angular field SIF observations over grass and chickpea canopies. Further, the coefficient of determination (R²) between the simulated SIF and field measurements was 0.75 (red) and 0.74 (far-red) for chickpea, and 0.65 (both red and far-red) for grass. The average relative error was approximately 3% for 1D homogeneous scenes when comparing the canopy-SIP SIF model simulations to the SCOPE model simulations, and around 4% for the 3D heterogeneous scene when comparing to the LESS model simulations. The results indicate that the proposed approach for separating asymmetric leaf SIF emissions is a robust way to keep a balance between satisfactory simulation accuracy and efficiency. Model simulations suggest that neglecting the leaf SIF asymmetry can lead to an underestimation of canopy red SIF by 6.3% to 42.6% for various leaf biochemical and canopy structural parameters. This study presents a simple but efficient analytical approach for canopy fluorescence modeling, with potential for large-scale canopy fluorescence simulations.
3D heterogeneous structure↗
Spin observables in proton-deuteron scattering and T-invariance test
The total cross section for the interaction of transversely polarized protons p{sub p}{sup y} and deuterons that have a tensor polarization P{sub x}{sup z} provides a null-test signal of T-invariance violation under the condition of P invariance. The relevant experiment is planned by the PAX Collaboration at the COSY accelerator with protons accelerated to the energy of 135 MeV. A modified Glauber theory is used here to calculate the differential spin observables A{sub y}, C{sub y,y}, C{sub xz,y}, C{sub z,x}, and C{sub x,z} and the differential and total cross sections for proton-deuteron scattering in the case of T-even P-even proton-nucleon interactions. This makes it possible to estimate background conditions of the planned experiment.
73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
Mechanistic and kinetic relevance of hydrogen and water in CO 2 hydrogenation on Cu-based catalysts
Here, we ally steady-state kinetics, kinetic isotope effects, and density functional theory (DFT) calculations to illustrate that Cu-based catalysts remain saturated by H-adatoms (H*) and molecular formic acid (HCOOH**) during CO 2 hydrogenation. High H* coverage under methanol synthesis conditions is evidenced by reverse water-gas shift (RWGS) rates that exhibit positive H 2 reaction orders only at P H2 ≲ 0.5 bar, above which methanol synthesis and RWGS rates exhibit first and zeroth order dependence on P H2 , respectively. HCOOH** also accumulates on the surface with increasing P CO2 as informed by the Langmuir-type dependence on P CO2 (0.25-23 bar) for both methanol synthesis and RWGS. As both HCOOH** and H* have one H-atom per site occupied, the two species share the same P H2 dependence and give rise to CO 2 reaction orders that are independent of P H2 . Surface coverages determined based on kinetic analyses are further corroborated with DFT-derived adsorption energies that show favorable HCOOH** adsorbate-adsorbate interactions as well as repulsive interactions for bidentate formate (HCOO**) on H*-saturated surfaces. Methanol selectivity remains invariant with P CO2 and P CO despite CO inhibiting reaction rates, thereby demonstrating methanol synthesis and RWGS occur on the same active site. In contrast, water preferentially inhibits methanol synthesis rates, increases methanol synthesis H 2 reaction order from 1.0 to 1.5, and alters the methanol synthesis H 2 /D 2 kinetic isotope effect; the inhibitory effect of H 2 O thus cannot be attributed to competitive adsorption alone and instead reflects a change in the rate-determining step for methanol synthesis. The disparate kinetics of methanol synthesis and RWGS evince a branching pathway where methanol is formed from formates and CO is formed from carboxylates. The presented work thus identifies the relevant surface species, underscores the distinct catalytic role of water in branching methanol synthesis and RWGS pathways, and, in doing so, details a mechanistic picture that yields predictable rates and reaction orders for both methanol synthesis and RWGS on Cu-based CO 2 hydrogenation catalysts.
37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CH↗
Measurement of proton electromagnetic form factors in the time-like region using initial state radiation at BESIII
The electromagnetic process e + e - → $p\bar{p}$ is studied with the initial-state-radiation technique using 7.5 fb -1 of data collected by the BESIII experiment at seven energy points from 3.773 to 4.600 GeV. The Born cross section and the effective form factor of the proton are measured from the production threshold to 3.0 GeV/c 2 using the $p\bar{p}$ invariant-mass spectrum. The ratio of electric and magnetic form factors of the proton is determined from the analysis of the proton-helicity angular distribution.
79 ASTRONOMY AND ASTROPHYSICS↗
Galvano-rotational effect induced by electroweak interactions in pulsars
We study electroweakly interacting particles in rotating matter. The existence of the electric current along the axis of the matter rotation is predicted in this system. This new galvano-rotational effect is caused by the parity violating interaction between massless charged particles in the rotating matter. We start with the exact solution of the Dirac equation for a fermion involved in the electroweak interaction in the rotating frame. This equation includes the noninertial effects. Then, using the obtained solution, we derive the induced electric current which turns out to flow along the rotation axis. We study the possibility of the appearance of the galvano-rotational effect in dense matter of compact astrophysical objects. The particular example of neutron and hypothetical quark stars is discussed. It is shown that, using this effect, one can expect the generation of toroidal magnetic fields comparable with poloidal ones in old millisecond pulsars. We also briefly discuss the generation of the magnetic helicity in these stars. Finally we analyze the possibility to apply the galvano-rotational effect for the description of the asymmetric neutrino emission from a neutron star to explain pulsars kicks.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
Fundamental Neutron Physics: Theory and Analysis
The goal of the proposal was to study the possibility of searching for manifestations of new physics beyond the Standard model in fundamental neutron physics experiments. This involves detailed theoretical analyses of parity- and time reversal invariance-violating processes in neutron-induced reactions, properties of neutron β-decay, and the precise description of properties of neutron interactions with nuclei. To describe neutron-nuclear interactions, we use both the effective field theory approach and the theory of nuclear reaction with phenomenological nucleon potentials for the systematic description of parity- and time reversal-violating effects in the consistent way. A major emphasis of our research during the funding period has been the study of parity violation (PV) and time reversal invariance violation (TRIV) in few-body systems. We studied PV effects in non-elastic processes in three-nucleon system using both ”DDH-like” and effective field theory (EFT) approaches. The wave functions were obtained by solving three-body Faddeev equations in configuration space for a number of realistic strong potentials. The observed model dependence for the DDH approach indicates intrinsic difficulty in the description of nuclear PV effects, and it could be the reason for the observed discrepancies in the nuclear PV data analysis. It shows that the DDH approach could be a reasonable approach for analysis of PV effects only if exactly the same strong and weak potentials are used in calculating all PV observables in all nuclei. However, the existing calculations of nuclear PV effects were performed using different potentials; therefore, strictly speaking, one cannot compare the existing results of these calculations among themselves.
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS↗
The effect of initial conditions on mixing transition of the Richtmyer–Meshkov instability
We investigate the late-time Richtmyer–Meshkov instability (RMI) growth of sinuous perturbations on an air/sulphur hexafluoride interface (Atwood number, A ~ 0.67 ) subjected to a Mach 1.2 planar shock wave at Los Alamos National Laboratory's vertical shock tube facility. Interface perturbations are established using a novel membraneless technique where cross-flowing air and SF 6 separated by an oscillating splitter plate create a perturbed density interface. The interface formed has multi-modal features and residual small perturbations, however, a dominant mode is still noticeable. The late-time perturbation growths scale with $ka_0$ initial conditions (where $k$ is the wavenumber and $a_0$ is the initial amplitude of the dominant mode) as measured at the pre-shock interface. Past nonlinear models based on potential-flow theory, heuristic/interpolation approaches, Padé approximants and numerical simulations are evaluated against present experimental results. Accounting for an explicit $ka_0$ dependence in Sadot et al.'s model, we propose an empirical rational function that captures the asymptotic behaviour of perturbation growth for a broad range of initial conditions ( 0.30 $≤ ka_0 ≤$ 0.86 ). The onset of mixing transition and its initial condition dependence are investigated with respect to the minimum state criterion ($Re =$ 1.6 $\times$ 10 5 ) for unsteady flows by Zhou. Earlier mixing transitions for higher ka0 initial conditions are noted from local and global Reynolds number estimates which are corroborated by the existence of an inertial sub-range and formation of mixing regions indicating the physical significance of the minimum state criterion in RMI flows. The transition is accompanied by the increasing teapot-like appearance of joint probability density functions of $p–q$ (invariants of the reduced velocity gradient tensor), establishing the technique as a useful tool for turbulence detection in two-dimensional diagnostics.
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSIC↗