scholarly journals Blast from the past: Constraints on the dark sector from the BEBC WA66 beam dump experiment

2021 ◽  
Vol 10 (2) ◽  
Author(s):  
Giacomo Marocco ◽  
Subir Sarkar

We derive limits on millicharged dark states, as well as particles with electric or magnetic dipole moments, from the number of observed forward electron scattering events at the Big European Bubble Chamber in the 1982 CERN-WA-066 beam dump experiment. The dark states are produced by the 400~GeV proton beam primarily through the decays of mesons produced in the beam dump, and the lack of excess events places bounds extending up to GeV masses. These improve on bounds from all other experiments, in particular CHARM~II.

2016 ◽  
Vol 13 (1) ◽  
pp. 146-154
Author(s):  
Baghdad Science Journal

In this paper the proton, neutron and matter density distributions and the corresponding root mean square (rms) radii of the ground states and the elastic magnetic electron scattering form factors and the magnetic dipole moments have been calculated for exotic nucleus of potassium isotopes K (A= 42, 43, 45, 47) based on the shell model using effective W0 interaction. The single-particle wave functions of harmonic-oscillator (HO) potential are used with the oscillator parameters b. According to this interaction, the valence nucleons are asummed to move in the d3f7 model space. The elastic magnetic electron scattering of the exotic nuclei 42K (J?T= 2- 2), 43K(J?T=3/2+ 5/2), 45K (J?T= 3/2+ 7/2) and 47K (J?T= 1/2+ 9/2) investigated through Plane Wave Born Approximation (PWBA). The inclusion of core polarization effect through the effective g-factors is adequate to obtain a good agreement between the predicted and the measured magnetic dipole moments.


2014 ◽  
Vol 60 ◽  
pp. 214-219
Author(s):  
V.N. Mal׳nev ◽  
Teshome Senbeta ◽  
Yohannes Achenefe

Radiocarbon ◽  
1997 ◽  
Vol 39 (1) ◽  
pp. 27-32 ◽  
Author(s):  
John C. Vogel ◽  
Joel Kronfeld

Twenty paired 14C and U/Th dates covering most of the past 50,000 yr have been obtained on a stalagmite from the Cango Caves in South Africa as well as some additional age-pairs on two stalagmites from Tasmania that partially fill a gap between 7 ka and 17 ka ago. After allowance is made for the initial apparent 14C ages, the age-pairs between 7 ka and 20 ka show satisfactory agreement with the coral data of Bard et al. (1990, 1993). The results for the Cango stalagmite between 25 ka and 50 ka show the 14C dates to be substantially younger than the U/Th dates except at 49 ka and 29 ka, where near correspondence occurs. The discrepancies may be explained by variations in 14C production caused by changes in the magnetic dipole field of the Earth. A tentative calibration curve for this period is offered.


2021 ◽  
Vol 2021 (3) ◽  
Author(s):  
Matthew J. Dolan ◽  
Torben Ferber ◽  
Christopher Hearty ◽  
Felix Kahlhoefer ◽  
Kai Schmidt-Hoberg

A mistake has been found in the numerical code used to reproduce the bounds from proton beam dump experiments from ref. [1] in figures 2 and 7 of ref. [2]. Correcting this mistake leads to slightly stronger bounds as shown below. We note that this correction does not include recent improvements in the analysis of proton beam dump experiments [3]. Additional recent bounds on GeV-scale ALPs can be found in refs. [4–8].


2021 ◽  
Vol 12 (4) ◽  
pp. 1124-1124
Author(s):  
Hiromu Kubo ◽  
Takashi Hirose ◽  
Takuya Nakashima ◽  
Tsuyoshi Kawai ◽  
Jun-ya Hasegawa ◽  
...  

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
D. Aristizabal Sierra ◽  
R. Branada ◽  
O. G. Miranda ◽  
G. Sanchez Garcia

Abstract With large active volume sizes dark matter direct detection experiments are sensitive to solar neutrino fluxes. Nuclear recoil signals are induced by 8B neutrinos, while electron recoils are mainly generated by the pp flux. Measurements of both processes offer an opportunity to test neutrino properties at low thresholds with fairly low backgrounds. In this paper we study the sensitivity of these experiments to neutrino magnetic dipole moments assuming 1, 10 and 40 tonne active volumes (representative of XENON1T, XENONnT and DARWIN), 0.3 keV and 1 keV thresholds. We show that with nuclear recoil measurements alone a 40 tonne detector could be as competitive as Borexino, TEXONO and GEMMA, with sensitivities of order 8.0 × 10−11μB at the 90% CL after one year of data taking. Electron recoil measurements will increase sensitivities way below these values allowing to test regions not excluded by astrophysical arguments. Using electron recoil data and depending on performance, the same detector will be able to explore values down to 4.0 × 10−12μB at the 90% CL in one year of data taking. By assuming a 200-tonne liquid xenon detector operating during 10 years, we conclude that sensitivities in this type of detectors will be of order 10−12μB. Reducing statistical uncertainties may enable improving sensitivities below these values.


2011 ◽  
Vol 11 (5&6) ◽  
pp. 444-455
Author(s):  
Knut Bakke ◽  
Cláudio Furtado

In this work, we propose a new formulation allowing to realize the holonomic quantum computation with neutral particles with a permanent magnetic dipole moments interacting with an external electric field in the presence of a topological defect. We show that both the interaction of the electric field with the magnetic dipole moment and the presence of topological defect generate independent contributions to the geometric quantum phases which can be used to describe any arbitrary rotation on the magnetic dipole moment without using the adiabatic approximation.


2020 ◽  
Vol 101 (7) ◽  
Author(s):  
Xiaoyong Chu ◽  
Jui-Lin Kuo ◽  
Josef Pradler

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