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M. Pitschmann

Publications and source records attributed to M. Pitschmann.

At least 19 recordsLinked to original sources
arXiv2022

UGR tests with atomic clocks and atom interferometers

Atomic interference experiments test the universality of the coupling between matter-energy and gravity at different spacetime points, thus being in principle able to probe possible violations of the universality of the gravitational redshift (UGR). In this contribution, we introduce a UGR violation model and then discuss UGR tests performed by atomic clocks and atom interferometers on the same footing. We present a large class of atom-interferometric geometries which are sensitive to violations of UGR.

gr-qc↗
arXiv2016

Exact Solution for Chameleon Field, Self-Coupled Through the Ratra-Peebles Potential with n = 1 and Confined Between Two Parallel Plates

We calculate the chameleon field profile, confined between two parallel plates, filled with air at pressure $P = 10^{-4}\,{\rm mbar}$ and room temperature and separated by the distance $L$, in the chameleon field theory with Ratra--Peebles self--interaction potential with index $n = 1$. We give the exact analytical solution in terms of Jacobian elliptic functions, depending on the mass density of the ambient matter. The obtained analytical solution can be used in qBounce experiments, measuring transition frequencies between quantum gravitational states of ultracold neutrons and also for the calculation of the chameleon field induced Casimir force for the CANNEX experiment. We show that the chameleon--matter interactions with coupling constants $\beta \le 10^4$ can be probed by qBounce experiments with sensitivities $\Delta E \le 10^{-18}\,{\rm eV}$. At $L = 30.1\,{\rm \mu m}$ we reproduce the result $\beta < 5.8\times 10^8$, obtained by Jenke {\it et al.} Phys. Rev. Lett. {\bf 112}, 151105 (2014)) at sensitivity $\Delta E \sim 10^{-14}\,{\rm eV}$. In the vicinity of one of the plates our solution coincides with the solution, obtained by Brax and Pignol (Phys. Rev. Lett. {\bf 107}, 111301 (2011)) (see also Ivanov {\it et al.} Phys. Rev. D {\bf 87}, 105013 (2013)) above a plate at zero density of the ambient matter.

gr-qc↗
arXiv2015

Effective Low-Energy Gravitational Potential for Slow Fermions Coupled to Linearised Massive Gravity

We analyse the Dirac equation for slow fermions coupled to linearised massive gravity above the Minkowski background and derive the effective low-energy gravitational potential. The obtained results can be used in terrestrial laboratories for the detection of gravitational waves and fluxes of massive gravitons emitted by cosmological objects. We also calculate the neutron spin precession within linearised massive gravity, which in principle can be measured by neutron interferometers.

gr-qc↗
arXiv2015

Neutron Interferometry constrains dark energy chameleon fields

We present phase shift measurements for neutron matter waves in vacuum and in low pressure Helium using a method originally developed for neutron scattering length measurements in neutron interferometry. We search for phase shifts associated with a coupling to scalar fields. We set stringent limits for a scalar chameleon field, a prominent quintessence dark energy candidate. We find that the coupling constant $\beta$ is less than 1.9 $\times10^7$~for $n=1$ at 95\% confidence level, where $n$ is an input parameter of the self--interaction of the chameleon field $\varphi$ inversely proportional to $\varphi^n$.

hep-ph↗
arXiv2014

Non-Relativistic Approximation of the Dirac Equation for Slow Fermions in Static Metric Spacetimes

We analyse the non-relativistic approximation of the Dirac equation for slow fermions moving in spacetimes with a static metric, caused by the weak gravitational field of the Earth and a chameleon field, and derive the most general effective gravitational potential, induced by a static metric of spacetime. The derivation of the non-relativistic Hamilton operator of the Dirac equation is carried out by using a standard Foldy-Wouthuysen (SFW) transformation. We discuss the chameleon field as source of a torsion field and torsion-matter interactions.

gr-qc↗
arXiv2014

The Bound-State Beta Decay of the Neutron Revisited

This paper is addressed to the analysis of the set of observables of the bound-state beta-decay, which can be used for the experimental investigation of contributions of i) interactions beyond the Standard Model (SM) and of ii) the left-handed polarisation state of antineutrinos. For this aim we calculate the branching ratio, probabilities and angular distributions of probabilities of hydrogen in the hyperfine states and of the proton-electron pair in different spinorial states, induced by left-handed and right-handed hadronic and leptonic currents. The branching ratio of the bound-state beta-decay is calculated by taking into account radiative corrections. We show that the probabilities of the bound-state beta-decay can be good observables for experimental investigations of contributions of interactions beyond the SM, whereas the angular distributions of probabilities are good observables for experimental searches of contributions of the left-handed polarisation state of antineutrinos.

hep-ph↗
arXiv2012

Neutron Beta-Decay as Laboratory for Test of Standard Model

We analyse the sensitivity of all experimentally observable asymmetries and energy distributions for the neutron beta-decay with a polarised neutron and unpolarised decay proton and electron and the lifetime of the neutron to contributions of order 10^(-4) of interactions beyond the Standard model (SM).

hep-ph↗
arXiv2011

Molecule model for deeply bound and broad kaonic nuclear clusters

A molecule model is proposed for the description of the properties of the kaonic nuclear cluster (KNC) anti-KNN with the structure N(ant-KN)_(I = 0) and quantum numbers I(J^P) = 1/2(0^-), the large binding energy B^(\exp)_(anti-KNN) = 103(6) MeV and the width Gamma^(\exp)_(anti-KNN) = 118(13) MeV, observed recently by the DISTO Collaboration. The theoretical values of the binding energy B^(th)_(anti-KNN) = 118 MeV, the width Gamma^(th)_(anti-KNN) = 142 MeV of the KNC anti-KNN and the density n_(anti-KNN) = 2.71 n_0, where n_0= 0.17 fm^(-3) is the normal nuclear density, reproduce well the large experimental values. They are calculated with the trial harmonic oscillator wave functions by using chiral Lagrangians, accounting for all self-energy terms, contributing to the masses of the kaonic nuclear clusters (anti-KN)_(I = 0) and anti-KNN. In addition the high Lambda*p sticking probability in the pp reaction at the kinetic energy T_p = 2.85 GeV of the incident proton is explained.

nucl-th↗
arXiv2010

Energy Level Displacement of Excited np State of Kaonic Deuterium In Faddeev Equation Approach

We calculate the energy level displacement of the excited $np$ state of kaonic deuterium in terms of the P-wave scattering length of $K^-d$ scattering. We solve the Faddeev equations for the amplitude of $K^-d$ scattering in the fixed centre approximation and derive the complex P-wave scattering length of $K^-d$ scattering in terms of the S-wave and P-wave scattering lengths of $\bar{K}N$ scattering. The estimated uncertainty of the complex P-wave scattering length is of about $15\,%$. For the calculated width $\Gamma_{2p} = 10.203\,{\rm meV}$ of the excited $2p$ state of kaonic deuterium we evaluate the yield $Y_{K^-d} = 0.27\,%$ of $X$-rays for the $K_{\alpha}$ emission line of kaonic deuterium. Using the complex S-wave and P-wave scattering lengths of $\bar{K}N$ scattering, calculated in \cite{ECL1,Weise1}, we get the width $\Gamma_{2p} = 2.675\,{\rm meV}$ of the excited $2p$ state and the yield $Y_{K^-d} = 1.90 \,%$ of $X$-rays for the $K_{\alpha}$ emission line of kaonic deuterium. The results, obtained in this paper, can be used for the planning of experiments on the measurements of the energy level displacement of the ground state of kaonic deuterium, caused by strong low-energy interactions.

nucl-th↗
arXiv2009

Molecule model for kaonic nuclear cluster anti-KNN

We analyse the properties of the kaonic nuclear cluster (KNC) anti-KNN with the structure Nx(anti-KN)_(I = 0), having the quantum numbers I(J^P) = 1/2(0^-), and treated as a quasi-bound hadronic molecule state. We describe the properties of the hadronic molecule, or the KNC Nx(anti-KN)_(I = 0), in terms of vibrational degrees of freedom with oscillator wave functions and chiral dynamics. These wave functions, having the meaning of trial wave functions of variational calculations, are parameterised by the frequency of oscillations of the (anti-KN)_(I = 0) pair, which is fixed in terms of the binding energy of the strange baryon resonance Lambda(1405), treated as a quasi-bound (anti-KN)_(I = 0) state. The binding energies B_X and widths Gamma_X of the states X = (anti-KN)_(I = 0) and X = anti-KNN, respectively, are calculated in the heavy-baryon approximation by using chiral Lagrangians with meson-baryon derivative couplings invariant under chiral SU(3)xSU(3) symmetry at the tree-level approximation. The results are B_(anti-KNN) = 40.2 MeV and Gamma_(anti-KNN) = Gamma^(non-pionic)_(anti-KNN) + Gamma^(pionic)_(anti-KNN) ~ (85 - 106) MeV and, where Gamma^(non-pionic)_(anti-KNN) ~ 21 MeV and Gamma^(pionic)_(anti-KNN) ~ (64 - 86) MeV are the widths of non-pionic anti-KNN -> N Lambda^0, N Sigma and pionic anti-KNN -> N Sigma pi decay modes, calculated for B_(anti-KN) = 29 MeV and Gamma_(anti-KN) = (30 - 40) MeV, respectively.

nucl-th↗
arXiv2009

On the influence of the magnetic field of the GSI experimental storage ring on the time-modulation of the EC-decay rates of the H-like mother ions

We investigate the influence of the magnetic field of the Experimental storage ring (ESR) at GSI on the periodic time-dependence of the orbital K-shell electron capture decay $(EC$) rates of the H--like heavy ions. We approximate the magnetic field of the ESR by a uniform magnetic field. Unlike the assertion by Lambiase et al., arXiv: 0811.2302 [nucl-th], we show that a motion of the H-like heavy ion in a uniform magnetic field cannot be the origin of the periodic time-dependence of the EC-decay rates of the H-like heavy ions.

nucl-th↗
arXiv2009

On Continuum-State and Bound-State Beta Decay Rates of the Neutron

We analyse the continuum-state and bound-state beta^-decay rates of the neutron. For the calculation of theoretical values of the decay rates we use the new value for the axial coupling constant g_A = 1.2750(9), obtained recently by H. Abele (Progr. Part. Nucl. Phys., 60, 1 (2008)) from the fit of the experimental data on the neutron spin-electron correlation coefficient of the electron energy spectrum of the continuum-state beta^- decay of the neutron. We take into account the contribution of radiative corrections and the scalar and tensor weak couplings. We define correlation coefficients of the electron energy spectrum in terms of axial, scalar and tensor coupling constants. Using recent precise experimental data for the lifetime of the neutron and correlation coefficients we estimate the scalar and tensor weak coupling constants. The bound-state beta^- decay rates of the neutron we calculate as functions of axial, scalar and tensor weak coupling constants. We show that dominantly the neutron decays into hydrogen in the hyperfine states with total angular momentum F = 0. The calculated angular distributions of the probabilities of the bound-state beta^- decays of the polarised neutron can be used for the experimental measurements of the bound-state beta^- decays into the hyperfine states with a total angular momentum F = 1.

hep-ph↗
arXiv2009

Rates of K-shell Electron Capture Decays of 180Re and 142Pm Atoms

We propose a theoretical analysis of the experimental data on the time behaviour K-shell electron capture (EC) decays of atoms 180Re and 142Pm in solid targets, obtained recently by Faestermann et al. Phys. Lett. B 672, 227 (2009) and Vetter et al., Phys. Lett. B 670, 149 (2008). We show that the absence of the time modulation in these data rules out the explanation of the "GSI Oscillations" (Yu. A. Litvinov et al., Phys. Lett. B 664, 162 (2008)) by means of two closely spaced ground mass-eigenstates of mother nuclei.

nucl-th↗
arXiv2009

Neutrino masses from the GSI anomaly

We investigate the influence of the strong Coulomb field of a heavy nucleus on massive neutrinos, produced in the K-shell electron capture (EC) decays of the H-like 140Pr58+ and 142Pm60+ ions. The corrections to the neutrino masses due to virtually produced charged lepton W-boson pairs in the strong Coulomb field of a nucleus with charge Ze are calculated and discussed with respect to their influence on the period of the time-modulation of the number of daughter ions, observed recently in the EC-decays of the H-like 140Pr58+ and 142Pm60+ ions at GSI in Darmstadt. These corrections explain the 2.9 times higher difference of the squared neutrino masses obtained from the time-modulation of the EC-decays with respect to the value deduced from the antineutrino-oscillation experiments of KamLAND.

nucl-th↗
arXiv2009

On Bound-State beta^- Decay Rate of the Free Neutron

We calculate the bound-state beta^- decay rate of the free neutron. We show that hydrogen in the final state of the decay is produced with a probability of about 99% in the hyperfine state with zero orbital l = 0 and atomic angular momentum F = 0.

hep-ph↗