arXiv subjects

T. Jenke

Publications and source records attributed to T. Jenke.

18 recordsLinked to original sources

arXiv2025

Fundamental Nuclear and Particle Physics At Neutron Sources

Fundamental neutron and neutrino physics at neutron sources, combining precision measurements and theory, can probe new physics at energy scales well beyond the highest energies probed by the LHC and possible future high energy collider facilities. The European Spallation Source (ESS) will in the not too far future be a most powerful pulsed neutron source and simultaneously the world's brightest pulsed neutrino source. The ESS, and neutron sources in general, can provide unprecedented and unique opportunities to contribute to the search for the missing elements in the Standard Model of particle physics. Currently there are no strong indications where hints of the origin of the new physics will emerge. A multi-pronged approach will provide the fastest path to fill the gaps in our knowledge and neutron sources have a pivotal role to play. To survey the ongoing and proposed physics experiments at neutron sources and assess their potential impact, a workshop was held at Lund University in January, 2025. This report is a summary of that workshop and has been prepared as input to the European Strategy Update.

nucl-ex↗

arXiv2023

A search for neutron-to-hidden-neutron oscillations in a ultra-cold neutron beam

Models that postulate the existence of hidden sectors address contemporary questions, such as the source of baryogenesis and the nature of dark matter. Among the possible mixing processes, neutron-to-hidden-neutron oscillations have been repeatedly tested with ultra-cold neutron storage and passing-through-wall experiments in the range of small ($\delta m<2$ peV) and large mass splitting ($\delta m>10$ neV), respectively. In this work, we present a new constraint in the oscillation parameter space derived from neutron disappearance in ultra-cold neutron beam experiments. The overall limit, which covers the intermediate mass-splitting range, is given by $\tau_{nn'}> 1$ s for $|\delta m| \in [2,69]$ peV (95\% C.L.).

hep-ph↗

arXiv2022

Particle Physics at the European Spallation Source

Presently under construction in Lund, Sweden, the European Spallation Source (ESS) will be the world's brightest neutron source. As such, it has the potential for a particle physics program with a unique reach and which is complementary to that available at other facilities. This paper describes proposed particle physics activities for the ESS. These encompass the exploitation of both the neutrons and neutrinos produced at the ESS for high precision (sensitivity) measurements (searches).

physics.ins-det↗

arXiv2022

$n-n'$ Oscillations: Sensitivity of a first UCN beam experiment

Oscillations of the neutron into a hidden sector particle are processes predicted in various Standard Model extensions. This extra channel for neutron disappearance has not been tested experimentally in large portions of the oscillation parameter space. Several efforts have been recently made on revising the oscillation time limits at low mass-splitting in ultra-cold neutron (UCN) storage experiments, and at larger mass-splitting in passing-through-wall experiments. In this work, we present the expected sensitivity of an experiment searching for neutron hidden neutron oscillations at intermediate mass-splitting via the application of magnetic fields in the range $B_0=30-1100$ $\mu$T. This experiment was performed at the Institut-Laue-Langevin using a novel UCN counter to monitor the beam flux. The measured UCN rate and the data collection technique predict a sensitivity on the oscillation time at the level of a couple of seconds.

nucl-ex↗

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↗

arXiv2022

Spatial resolution determination of a position sensitive ultra-cold neutron detector

The study of the properties of the quantum states of bouncing neutrons requires position sensitive detection with micro-metric spatial resolution. The UCNBoX detector relies on Charge Coupled Devices (CCD) coated with a thin boron-10 conversion layer to detect neutron hits. In this paper, we present an original experimental method to determine the spatial resolution of this device using micrometric masks. The observed resolution is $2.0\pm0.3~\mu$m.

physics.ins-det↗

arXiv2020

Light and Slow-Neutron Diffraction by Nanodiamond-Dispersed Nanocomposite Holographic Gratings

We demonstrate the use of nanodiamond in constructing holographic nanoparticle-polymer composite transmission gratings with large saturated refractive index modulation amplitudes at both optical and slow-neutron wavelengths, resulting in efficient control of light and slow-neutron beams. Nanodiamond possesses a high refractive index at optical wavelengths and large coherent and small incoherent scattering cross sections with low absorption at slow-neutron wavelengths. We describe the synthesis of nanodiamond, the preparation of photopolymerizable nanodiamond-polymer composite films, the construction of transmission gratings in nanodiamond-polymer composite films and light optical diffraction experiments. Results of slow-neutron diffraction from such gratings are also presented.

physics.optics↗

arXiv2017

Neutron lifetime measurements with the big gravitational trap for ultracold neutrons

Neutron lifetime is one of the most important physical constants which determines parameters of the weak interaction and predictions of primordial nucleosynthesis theory. There remains the unsolved problem of a 3.9{\sigma} discrepancy between measurements of this lifetime using neutrons in beams and those with stored neutrons (UCN). In our experiment we measure the lifetime of neutrons trapped by Earth's gravity in an open-topped vessel. Two configurations of the trap geometry are used to change the mean frequency of UCN collisions with the surfaces - this is achieved by plunging an additional surface into the trap without breaking the vacuum. The trap walls are coated with a hydrogen-less fluorine-containing polymer to reduce losses of UCN. The stability of this coating to multiple thermal cycles between 80 K and 300 K was tested. At 80 K, the probability of UCN loss due to collisions with the trap walls is just 1.5% of the probability of beta-decay. The free neutron lifetime is determined by extrapolation to an infinitely large trap with zero collision frequency. The result of these measurements is 881.5 +/- 0.7_stat +/- 0.6_syst s which is consistent with the conventional value of 880.2 +/- 1.0 s presented by the Particle Data Group. Future prospects for this experiment are in further cooling to 10 K which will lead to an improved accuracy of measurement. In conclusion we present an analysis of currently-available data on various measurements of the neutron lifetime.

nucl-ex↗

arXiv2016

Comparison of ultracold neutron sources for fundamental physics measurements

Ultracold neutrons (UCNs) are key for precision studies of fundamental parameters of the neutron and in searches for new CP violating processes or exotic interactions beyond the Standard Model of particle physics. The most prominent example is the search for a permanent electric dipole moment of the neutron (nEDM). We have performed an experimental comparison of the leading UCN sources currently operating. We have used a 'standard' UCN storage bottle with a volume of 32 liters, comparable in size to nEDM experiments, which allows us to compare the UCN density available at a given beam port.

physics.ins-det↗

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

A Gravity of Earth Measurement with a qBOUNCE Experiment

We report a measurement of the local acceleration $g$ with ultracold neutrons based on quantum states in the gravity potential of the Earth. The new method uses resonant transitions between the states $|1> -> |3>$ and for the first time between $|1> -> |4>$. The measurements demonstrate that Newton's Inverse Square Law of Gravity is understood at micron distances at an energy level of $10^{-14}$ eV with $\frac{\Delta g}{g}=4\times10^{-3}$. The results provide constraints on any possible gravity-like interaction at a micrometer interaction range. In particular, a dark energy candidate, the chameleon field is restricted to $\beta<6.9\times10^{6}$ for $n=2$ (95\% C.L.).

hep-ex↗

arXiv2015

Gravity experiments with ultracold neutrons and the qBounce experiment

This work focuses on the control and understanding of a gravitationally interacting elementary quantum system. It offers a new way of looking at gravitation based on quantum interference: an ultracold neutron, a quantum particle, as an object and as a tool. The ultracold neutron as a tool reflects from a mirror in well-defined quantum states in the gravity potential of the earth allowing to apply the concept of gravity resonance spectroscopy (GRS). GRS relies on frequency measurements, which provide a spectacular sensitivity.

physics.ins-det↗

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

Gravity Resonance Spectroscopy Constrains Dark Energy and Dark Matter Scenarios

We report on precision resonance spectroscopy measurements of quantum states of ultracold neutrons confined above the surface of a horizontal mirror by the gravity potential of the Earth. Resonant transitions between several of the lowest quantum states are observed for the first time. These measurements demonstrate, that Newton's inverse square law of Gravity is understood at micron distances on an energy scale of~$10^{-14}$~eV. At this level of precision we are able to provide constraints on any possible gravity-like interaction. In particular, a dark energy chameleon field is excluded for values of the coupling constant~$β> 5.8\times10^8$ at~95% confidence level~(C.L.), and an attractive (repulsive) dark matter axion-like spin-mass coupling is excluded for the coupling strength $g_sg_p > 3.7\times10^{-16}$~($5.3\times10^{-16}$)~at a Yukawa length of~$λ= 20$~{\textmu}m~(95% (C.L.).

gr-qc↗

arXiv2014

Vectorial velocity filter for ultracold neutrons based on a surface-disordered mirror system

We perform classical three-dimensional Monte Carlo simulations of ultracold neutrons scattering through an absorbing-reflecting mirror system in the Earth's gravitational field. We show that the underlying mixed phase space of regular skipping motion and random motion due to disorder scattering can be exploited to realize a vectorial velocity filter for ultracold neutrons. The absorbing-reflecting mirror system proposed allows beams of ultracold neutrons with low angular divergence to be formed. The range of velocity components can be controlled by adjusting the geometric parameters of the system. First experimental tests of its performance are presented. One potential future application is the investigation of transport and scattering dynamics in confined systems downstream of the filter.

hep-ph↗

arXiv2012

A quantized frequency reference in the short-ranged gravity potential and its application for dark matter and dark energy searches

The evidence for the observation of the Higgs spin-0-boson as a manifestation of a scalar field provides the missing corner stone for the standard model of particles (SM). However, the SM fails to explain the non-visible but gravitationally active part of the universe. Its nature is unknown but the confirmation of a scalar Higgs is giving a boost to scalar-field-theories. So far gravity experiments and observations performed at different distances find no deviation from Newton's gravity law. Therefore dark energy must possess a screening mechanism which suppresses the scalar-mediated fifth force. Our line of attack is a novel gravity experiment with neutrons based on a quantum interference technique. The spectroscopic measurement of quantum states on resonances with an external coupling makes this a powerful search for dark matter and dark energy contributions in the universe. Quantum states in the gravity potential are intimately related to other scalar field or spin-0-bosons if they exist. If the reason is that some undiscovered particle interact with a neutron, this results in a measurable energy shift of quantum states in the gravity potential, because for neutrons the screening effect is absent. We use Gravity Resonance Spectroscopy to measure the energy splitting at the highest level of precision, providing a constraint on any possible new interaction. We obtain a sensitivity of 10^-14 eV. We set an experimental limit on any fifth force, in particular on parameter β<2x10^9 at n=3 for the scalar chameleon field, which is improved by a factor of 100 compared to our previous experiment and five orders of magnitude better than from precision tests of atomic spectra. The pseudoscalar axion coupling is constrained to gsgp/\hbar c<3x10^-16 at 20μm, which is an improvement by a factor of 30. These results indicate that gravity is understood at this improved level of precision.

hep-ex↗

arXiv2012

The influence of the chameleon field potential on transition frequencies of gravitationally bound quantum states of ultra-cold neutrons

We calculate the chameleon field potential for ultracold neutrons, bouncing on top of one or between two neutron mirrors in the gravitational field of the Earth. For the resulting non--linear equations of motion we give approximate analytical solutions and compare them with exact numerical ones for which we propose the analytical fit. The obtained solutions may be used for the quantitative analysis of contributions of a chameleon field to the transition frequencies of quantum states of ultra-cold neutrons bound in the gravitational field of the Earth.

hep-th↗

arXiv2009

Ramsey's Method of Separated Oscillating Fields and its Application to Gravitationally Induced Quantum Phaseshifts

We propose to apply Ramsey's method of separated oscillating fields to the spectroscopy of the quantum states in the gravity potential above a vertical mirror. This method allows a precise measurement of quantum mechanical phaseshifts of a Schrödinger wave packet bouncing off a hard surface in the gravitational field of the earth. Measurements with ultra-cold neutrons will offer a sensitivity to Newton's law or hypothetical short-ranged interactions, which is about 21 orders of magnitude below the energy scale of electromagnetism.

nucl-ex↗