New method of galactic axion search Sasao, N.; Yoshimura, M.
European physical journal. C, Particles and fields,
11/2018, Volume:
78, Issue:
11
Journal Article
Peer reviewed
Open access
An appealing candidate of the galactic dark matter is the axion, which was postulated to solve the strong CP (Charge-conjugation Parity) violation problem in the standard particle theory. A new ...experimental method is proposed to determine the axion mass. The method uses collectively and coherently excited atoms or molecules, the trigger laser inducing galactic axion absorption along with signal photon emission to be detected.
The recent proposal of a photon and a neutrino-pair beam is investigated in detail. Production rates, both differential and total, of a single photon, two photons, and a neutrino pair emitted from ...quantum ions in circular motion are given for any velocity of ion. This part is an extension of our previous calculations at highest energies to lower energies of circulating ions, and hopefully helps to identify the new process of quantum ion circulation at a low energy ring. We clarify how to utilize the circulating ion for a new source of coherent neutrino beam despite much stronger background photons. Once one verifies that the coherence is maintained in the initial phases of time evolution after laser irradiation, large background photon emission rates are not an obstacle against utilizing the extracted neutrino-pair beam.
Neutrino oscillation experiments under neutrino pair beam from circulating excited heavy ions are studied. It is found that detection of double weak events has a good sensitivity to measure CP ...violating parameter and distinguish mass hierarchy patterns in short baseline experiments in which the earth-induced matter effect is minimized.
A new scheme to determine the neutrino mass matrix is proposed using atomic de-excitation between two states of a few eV energy spacing. The determination of the smallest neutrino mass of the order ...of 1 meV and neutrino mass type, Majorana or Dirac, becomes possible, if one can coherently excite more than 1 gram of atoms using two lasers.
The process of collective de-excitation of atoms in a metastable level into emission mode of a single photon plus a neutrino pair, called radiative emission of neutrino pair (RENP), is sensitive to ...the absolute neutrino mass scale, to the neutrino mass hierarchy and to the nature (Dirac or Majorana) of massive neutrinos. We investigate how the indicated neutrino mass and mixing observables can be determined from the measurement of the corresponding continuous photon spectrum taking the example of a transition between specific levels of the Yb atom. The possibility of determining the nature of massive neutrinos and, if neutrinos are Majorana fermions, of obtaining information about the Majorana phases in the neutrino mixing matrix, is analyzed in the cases of normal hierarchical, inverted hierarchical and quasi-degenerate types of neutrino mass spectrum. We find, in particular, that the sensitivity to the nature of massive neutrinos depends critically on the atomic level energy difference relevant in the RENP.
CsI calorimeter for the J-PARC KOTO experiment Sato, K.; Lee, J.W.; Banno, S. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
12/2020, Volume:
982, Issue:
C
Journal Article
Peer reviewed
Open access
An electromagnetic calorimeter made of undoped CsI crystals is used in the J-PARC KOTO experiment to search for new physics beyond the standard model with the KL→π0νν̄ decay. The calorimeter is ...designed to operate in vacuum of 0.1 Pa and in a high-rate environment where the counting rate due to KL decays is O(100) kHz. A special method to calibrate the calorimeter during the data taking without using a tracking system for charged particles is reported. The energy, position, and timing resolutions of the calorimeter were evaluated in several beam tests, and the resolutions satisfy the required performance. The energy resolution with the total energy E is 0.66⊕1.81∕EGeV% in the inner region of the calorimeter.
This paper reports on the demonstration of a high-rate energy measurement technique using a thin depletion layer silicon avalanche photodiode (Si-APD). A dedicated amplitude-to-time converter is ...developed to realize simultaneous energy and timing measurement in a high rate condition. The energy response of the system is systematically studied by using monochromatic X-ray beam with an incident energy ranging from 6 to 33 keV. The obtained energy spectra contain clear peaks and tail distributions. The peak fraction monotonously decreases as the incident photon energy increases. This phenomenon can be explained by considering the distribution of the energy deposit in silicon, which is investigated by using a Monte Carlo simulation.
We derive for the first time fundamental equations that describe soliton spatial profiles consisting of two-photon mode fields and macroscopic polarization of a medium. Numerical solutions of this ...basic equation are presented to suggest both single soliton and multiple soliton chains in infinitely long targets, using the example of para-H
$_2$
$v=0 \leftrightarrow 1$
(E1 forbidden) vibrational parameters. Although the effects of dissipative relaxation are included in the general form for the two-level system, the existence of a static soliton condensate is established. For finite-size targets, we can precisely formulate the profile equation in the framework of a nonlinear eigenvalue problem. Its first iteration provides approximate semi-analytic results under a potential well in the linearized equation; these results have qualitatively similar profiles to the case of an infinitely long target, an important difference being the exponentially decreasing profile near target ends. A large number of weakly interacting solitons correspond to localized portions between adjacent nodes of highly excited bound-state wave functions in a 1D potential well of large size. These soliton condensates are expected to be important in enhancing the signal to the background ratio in the proposed neutrino mass spectroscopy using atoms.
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