scholarly journals NUCLEON-NUCLEON PARITY VIOLATION EXPERIMENTS

1999 ◽  
Vol 08 (05) ◽  
pp. 417-442 ◽  
Author(s):  
WILLEM T. H. VAN OERS
Keyword(s):  
Parity Violation ◽  
Transition Amplitude ◽  
Nucleon Nucleon ◽  
Coupling Constants ◽  
Meson Exchange ◽  
Strong Interactions ◽  
Coupling Constant ◽  
Proton Proton ◽  
Analyzing Powers ◽  
Energy Domain

Measurements of parity-violating longitudinal analyzing powers Az (normalized asymmetries) in polarized proton-proton scattering and in polarized neutron capture on the proton (n-p→d - γ) provide a unique window on the interplay between the weak and strong interactions between and within hadrons. Several new proton-proton parity violation experiments are presently either being performed or are being prepared for execution in the near future: at TRIUMF at 221 MeV and 450 MeV and at COSY (Forschungszentrum Jülich) in the multi-GeV range. A new measurement of the parity-violating γ ray asymmetry with a ten-fold improvement in the accuracy over previous measurements is being developed at LANSCE. These experiments are intended to provide stringent constraints on the set of six effective weak meson-nucleon coupling constants, which characterize the weak interaction between hadrons in the energy domain where meson exchange models provide an appropriate description. The 221 MeV p - p experiment is unique in that it selects a single transition amplitude (3P2-1D2) and consequently constrains the weak meson-nucleon coupling constant [Formula: see text]. The n-p→d-γ experiment is mainly sensitive to the weak pion-nucleon coupling constant fπ. Together with the existing p-p parity violation experimental results one may be able to delineate the various weak meson-nucleon coupling constants. The TRIUMF 221 MeV p-p parity violation experiment will be described in some detail. Other parity violation nucleon-nucleon and nucleon-very-light-nucleus experiments are commented on. The anomalous result obtained at 6 GeV/c on a water target requires that a new multi-GeV p-p parity violation experiment be performed.

PARITY VIOLATION IN FEW-NUCLEON SYSTEMS: WHERE DO WE STAND?

1990 ◽  
Vol 05 (22) ◽  
pp. 1703-1715 ◽  
Author(s):  
ULF-G. MEIβNER
Keyword(s):  
Parity Violation ◽  
Experimental Studies ◽  
Nucleon Nucleon ◽  
Meson Exchange ◽  
Coupling Constant ◽  
Proton Proton ◽  
Nucleon Potential ◽  
Longitudinal Asymmetry ◽  
Low Energies ◽  
Pion Nucleon

We review the present status of our understanding of parity violation in few-nucleon systems. At low energies, nuclear parity-violating forces can be parametrized in the framework of meson-exchange potentials. The pertinent weak meson-nucleon couplings can be calculated by invoking either the quark or the soliton model of the low-lying baryons. We compare the resulting couplings and discuss the advantages and limitations of both approaches. Then, we turn to the experimental study of nuclear parity violation in few-nucleon systems. First, we review various calculations of the longitudinal asymmetry in proton-proton scattering with an eye on the upcoming high-precision experiment at TRIUMF. We stress the importance of a consistent calculation of the weak and strong nucleon-nucleon potential. A toy calculation is presented for the photo-disintegration of the dueteron, which appears to be an excellent candidate to pin down the parity-violating pion-nucleon coupling constant. We encourage further theoretical as well as experimental studies.

Internal motion in benzylidene diacetate and its 2,6-dibromo derivative by DNMR and the J method

1989 ◽  
Vol 67 (6) ◽  
pp. 1022-1026 ◽  
Author(s):  
Ted Schaefer ◽  
Craig S. Takeguchi
Keyword(s):  
Double Resonance ◽  
Coupling Constants ◽  
Spin Coupling ◽  
Maximum Magnitude ◽  
Coupling Constant ◽  
Spectral Parameters ◽  
Proton Proton ◽  
Ether Solution ◽  
Spin Spin Coupling ◽  
Dibromo Derivative

The 1H nuclear magnetic resonance spectral parameters are reported for benzylidene diacetate in CS2 and acetone-d6 solutions. The long-range spin–spin coupling constant over six formal bonds, 6J, is used to derive apparent twofold barriers to rotation about the exocyclic C(1)—C bond in the two solutions. The conformation of lowest energy has the α. C—H bond in the benzene plane. The barrier is higher in CS2 than in acetone-d6 solution, in contrast to a molecule like benzyl chloride. In the 2,6-dibromo derivative, the free energy of activation for reorientation about the bond in question is 36 kJ/mol at 165 K in dimethyl ether solution. Such a high barrier implies a very small six-bond proton–proton coupling constant for this derivative because 6J is proportional to the expectation value of sin2θ. The angle θ is zero when the α C—H bond lies in the benzene plane. 6J is −0.051 Hz in acetone-d6 solutions; its sign is determined by double resonance experiments. The question of an angle-independent component of 6J, that is, whether 6J is finite at θ = 0°, is addressed. A maximum magnitude of 0.02 Hz may be present at θ = 0° for the 2,6-dibromo derivative, although a zero magnitude is also compatible with the experimental data. In a compound with a higher internal barrier, α,α,2,6-tetrachlorotoluene, the experimental results are best in accord with a negligibly small 6J at θ = 0°. Keywords: 1H NMR of benzylidene diacetate, spin–spin coupling constants for benzylidene diacetate, DNMR, 2,6-dibromobenzylidene diacetate.

scholarly journals Energy Dependence of Slope Parameter in Elastic Nucleon-Nucleon Scattering

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
V. A. Okorokov
Keyword(s):  
Experimental Data ◽  
Energy Dependence ◽  
Nucleon Nucleon ◽  
High Energy ◽  
Slope Parameter ◽  
Proton Antiproton ◽  
Proton Proton ◽  
Elastic Proton ◽  
Energy Domain ◽  
Very High Energy

The diffraction slope parameter is investigated for elastic proton-proton and proton-antiproton scattering based on all the available experimental data at low and intermediate momentum transfer values. Energy dependence of the elastic diffraction slope is approximated by various analytic functions. The expanded “standard” logarithmic approximations with minimum number of free parameters allow description of the experimental slopes in all the available energy range reasonably. The estimations of asymptotic shrinkage parameterαP′are obtained for various|t|domains based on all the available experimental data. Various approximations differ from each other both in the low energy and very high energy domains. Predictions for diffraction slope parameter are obtained for elastic proton-proton scattering from NICA up to future collider (FCC/VLHC) energies, for proton-antiproton elastic reaction in FAIR energy domain for various approximation functions.

Studies on the PMR Spectra of Oxetanes. VI 2-(3-Chlorophenyl)oxetane and 2-(2-Chlorophenyl)oxetane at 60 and 100 MHz

1974 ◽  
Vol 29 (12) ◽  
pp. 1902-1906 ◽  
Author(s):  
Jukka Jokisaari
Keyword(s):  
Long Range ◽  
Chemical Shifts ◽  
Methine Proton ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Proton Proton ◽  
Temperature Range ◽  
Proton Coupling ◽  
Phenyl Proton ◽  
Pmr Spectra

The 100 MHz spectra of the phenyl protons in 2-(3-chlorophenyl) oxetane and 2-(2-chlorophenyl) oxetane have been analysed. The 60 MHz PMR chemical shifts and proton-proton coupling constants have been studied in the temperature range from -20 C to +80 °C. The chemical shifts were sensitive to temperature, while the coupling constants were not, except the long range 5Jm coupling constant between the methine proton and the meta positioned phenyl proton in 2-(2-chlorophenyl) oxetane.

ELASTIC PROTON-PROTON SCATTERING AT GEV ENERGIES: ANALYZING POWERS ANAND SPIN CORRELATION PARAMETERS ANN, ASS, AND ASL

2005 ◽  
Vol 20 (08n09) ◽  
pp. 1959-1962
Author(s):  
◽  
F. HINTERBERGER ◽  
K. O. EYSER
Keyword(s):  
Phase Shift ◽  
Spin Correlation ◽  
Meson Exchange ◽  
Proton Scattering ◽  
Excitation Functions ◽  
Proton Proton ◽  
Analyzing Powers ◽  
Elastic Proton ◽  
Correlation Parameters ◽  
Spin Correlation Parameters

The analyzing powers ANand spin correlation parameters ANN, ASS, and ASLof the elastic proton-proton scattering have been measured with an internal polarized atomic beam target at the cooler synchrotron COSY. Excitation functions were taken continuously during the acceleration and deceleration of the internal beam for kinetic energies ranging between 0.45 and 2.5 GeV and scattering angles 30°≤Θc.m.≤90°. The analyzing power excitation functions provide a new polarization standard in the GeV region. The spin correlation data on ASSdisagree strikingly with existing phase shift solutions. The addition of the new polarization data to the world database removes some of the ambiguities in the phase shift solutions and the direct reconstruction of scattering amplitudes. The data are compared with a recent extension of a meson-exchange potential model to higher energies.

An 1H NMR conformational analysis of 3-phenylpentane in solution

1993 ◽  
Vol 71 (4) ◽  
pp. 520-525 ◽  
Author(s):  
Ted Schaefer ◽  
Lina B.-L. Lee
Keyword(s):  
Alkyl Chain ◽  
Chemical Shifts ◽  
Close Approach ◽  
Solvent Mixture ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Proton Proton ◽  
Vicinal Coupling Constants ◽  
Proton Coupling ◽  
Proton Chemical Shifts

Some 30 proton chemical shifts and proton–proton coupling constants are reported for a 4.7 mol% solution of 3-phenylpentane in a CS2/C6D12/TMS solvent mixture at 300 K. The long-range coupling constant over six formal bonds between the methine and para protons is used to deduce an apparent twofold barrier of 15.0 ± 0.3 kJ/mol to rotation about the Csp2—Csp3 bond, at least twice as large as that for isopropylbenzene in solution. AM1 computations agree with experiment in finding the conformation of lowest energy as that in which the methine C—H bond is situated in the phenyl plane, but predict a barrier height of only 13.9 kJ/mol. The vicinal coupling constants are consistent with a fractional population, 0.38(2), of the TT conformer, that in which all the carbon atoms of the alkyl chain lie in a plane. A doubly degenerate conformer, TG+(G−T), in which one methyl group is twisted away from the phenyl substituent, then has a fractional population of 0.62(2). The assumption that only these three conformers are present is tested with the signs and magnitudes of the four different coupling constants over four bonds. These coupling constants are consistent with the absence of significant proportions of the other six all-staggered conformers. These six are characterized by a close approach of the methyl groups (1,5 interactions) or by proximity of the methyl and phenyl moieties.

The effect of substituents on geminal proton–proton coupling constants. III

1977 ◽  
Vol 55 (14) ◽  
pp. 2642-2648 ◽  
Author(s):  
Roger N. Renaud ◽  
John W. Bovenkamp ◽  
Robert R. Fraser ◽  
Raj Capoor
Keyword(s):  
Coupling Constants ◽  
Coupling Constant ◽  
Mo Calculations ◽  
Proton Proton ◽  
Effect Of Substituents ◽  
Proton Coupling ◽  
Geminal Proton ◽  
Geminal Coupling ◽  
The Difference ◽  
Methylene Group

The effect of substituents at the 3-position in a series of N-methyl 5,6-dihydro-7H,12H-di-benzo[c,f]azocines on the geminal coupling constants of the C-12 methylene protons has been determined. The slope of the Hammett plot of 2J vs. σ has been found to be +0.20. The orientation of the methylene protons with respect to the π orbitals of the benzene ring bearing the substituent is such that no hyperconjugative effect should be present. The value of +0.20 is in contrast to a previously measured slope of −1.9 for compounds having a geometry ideal for hyperconjugative effects and substantiates the predictions of theoretical MO calculations. As a result, the reliability of this conformational dependence of ρ for use in conformational analysis has been strengthened.A comparison of the data for the azocines with those in the literature indicates the difference between the minimum and maximum effects of a phenyl substituent on a geminal coupling constant of an attached methylene group is 5.5 Hz.

The relationship between carbon-13 substituent chemical shifts and proton coupling constants in aza-aromatic systems

1984 ◽  
Vol 37 (2) ◽  
pp. 311 ◽  
Author(s):  
IB Cook ◽  
S Pengprecha ◽  
B Ternai
Keyword(s):  
Experimental Data ◽  
Chemical Shift ◽  
Chemical Shifts ◽  
Coupling Constants ◽  
Coupling Constant ◽  
Proton Proton ◽  
Proton Coupling ◽  
Substituted Pyridines ◽  
Aromatic Systems ◽  
The Relationship

An equation which relates the ortho carbon-13 substituent chemical shift α-SCS in aza-aromatics to the ortho proton-proton coupling constant 3J(HH) in the corresponding carbocyclic compound is derived from experimental data. The implications for N-N bond fixation in diaza-aromatics are discussed. When the equation is applied to 2-substituted pyridines, an electronegativity parameter must be included to explain the results.

scholarly journals OPEN CHARM ANALYSIS ON THE FIRST PP COLLISIONS AT $\sqrt{s} = 7~{\rm TeV}$ WITH ALICE

2011 ◽  
Vol 02 ◽  
pp. 25-30 ◽  
Author(s):  
◽  
GIACOMO ORTONA
Keyword(s):  
Production Cross ◽  
Hadron Collider ◽  
Heavy Ion ◽  
Nucleon Nucleon ◽  
Relativistic Heavy Ion Collisions ◽  
Alice Experiment ◽  
Proton Proton ◽  
Ion Collisions ◽  
Density State ◽  
Energy Domain

A Large Ion Collider Experiment (ALICE) is one of the four large experiments at the Large Hadron Collider (LHC), and the one dedicated to ultra relativistic heavy ion collisions, aiming at investigating the properties of the high-density state of QCD matter produced in such events. ALICE started to collect data in proton-proton collisions at the LHC at CERN in November 2009 (with a centre of mass energy [Formula: see text]). Since March 2010 data are being recorded at an energy of [Formula: see text] while from November 7 to December 6 LHC provided Pb-Pb collisions at an energy of [Formula: see text] per nucleon-nucleon pair. In Pb-Pb collisions heavy quarks are regarded as sensitive probes of the interaction dynamics between the parton and medium produced in the collisions, and the energies available at LHC will allow to study the production of heavy flavours with high statistics. Proton-proton data will be used to measure the heavy flavours production cross section to compare with perturbative QCD calculations in an unexplored energy domain and they will provide the reference for the study of Pb-Pb collisions. After a description of the ALICE experiment focused on its heavy flavour related performance, the status of the first analysis on charm production, measured by reconstructing the decays of D0, D+, D*+, and Ds into hadronic and semi-leptonic channels will be presented. An outlook of the same measurements for the upcoming Pb-Pb run will also be discussed.

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