scholarly journals Searching for dark sector with missing mass technique in fixed target experiments

2019 ◽  
Vol 212 ◽  
pp. 06001 ◽  
Author(s):  
Venelin Kozhuharov
Keyword(s):  
Final States ◽  
Dark Sector ◽  
Initial State ◽  
Missing Mass ◽  
Fixed Target Experiments ◽  
Hidden Sector ◽  
Dark Photon ◽  
Precise Knowledge ◽  
Viable Solution ◽  
Experimental Approaches

Currently, the existence of a dark sector almost completely decoupled from the Standard Model is a viable solution for numerous long-standing problems in physics, including the nature of dark matter and the muon anomalous magnetic moment. A new gauge mediator, the dark photon, could be the portal to this hidden sector. The most general probe to its existence is the missing mass technique which requires a precise knowledge of the initial state of the process but does not put constraints on the dark photon final states. The experimental approaches to the search for dark photons in positron-on-target annihilation and in mesons decay in flight are presented and the physics reach is discussed.

scholarly journals Search for dark forces at KLOE-2

2019 ◽  
Vol 212 ◽  
pp. 06002
Author(s):  
Elena Perez del Rio
Keyword(s):  
Standard Model ◽  
Model Parameters ◽  
Vector Particle ◽  
Beyond The Standard Model ◽  
Final States ◽  
Dark Sector ◽  
Dark Photon ◽  
The Standard Model ◽  
Discovery Potential ◽  
Breaking Mechanism

During the last years several Dark Sector Models have been proposed in order to address striking and puzzling astrophysical observations which fail standard interpretations. In the minimal case a new vector particle, the so called dark photon or U-boson, is introduced, with small coupling with Standard Model particles. Also, the existence of a dark Higgs boson h’ is postulated, in analogy with the Standard Model, to give mass to the U-boson through the Spontaneous Symmetry Breaking mechanism. The discovery of such a Dark Force Mediator would belong to a new field of Physics Beyond the Standard Model. The KLOE experiment, working on the DAΦNE e+e− collider in Frascati, searched for the existence of the U-boson in a quite complete way, investigating several different processes and final states. Tight limits on the model parameters have been set at 90%CL. Further improvements are expected in terms of sensitivity and discovery potential with the new KLOE-2 detector working on the improved DAΦNE e+e− collider, which has collected more than 5 fb−1.

scholarly journals Xenon-1T excess as a possible signal of a sub-GeV hidden sector dark matter

2021 ◽  
Vol 2021 (2) ◽  
Author(s):  
Amin Aboubrahim ◽  
Michael Klasen ◽  
Pran Nath
Keyword(s):  
Dark Matter ◽  
Particle Physics ◽  
Small Mass ◽  
Big Bang ◽  
Mass Splitting ◽  
Recoil Energy ◽  
Dirac Fermions ◽  
Dark Sector ◽  
Dark Photon ◽  
Physics Model

Abstract We present a particle physics model to explain the observed enhancement in the Xenon-1T data at an electron recoil energy of 2.5 keV. The model is based on a U(1) extension of the Standard Model where the dark sector consists of two essentially mass degenerate Dirac fermions in the sub-GeV region with a small mass splitting interacting with a dark photon. The dark photon is unstable and decays before the big bang nucleosynthesis, which leads to the dark matter constituted of two essentially mass degenerate Dirac fermions. The Xenon-1T excess is computed via the inelastic exothermic scattering of the heavier dark fermion from a bound electron in xenon to the lighter dark fermion producing the observed excess events in the recoil electron energy. The model can be tested with further data from Xenon-1T and in future experiments such as SuperCDMS.

scholarly journals Supernova constraints on an axion-photon-dark photon interaction

2021 ◽  
Vol 2021 (6) ◽  
Author(s):  
Anson Hook ◽  
Gustavo Marques-Tavares ◽  
Clayton Ristow
Keyword(s):  
Longitudinal Mode ◽  
Transverse Mode ◽  
The Other ◽  
Unusual Feature ◽  
Dark Sector ◽  
Longitudinal Modes ◽  
Dark Photon ◽  
Transverse Modes ◽  
Weakly Coupled ◽  
Photon Coupling

Abstract We present the supernova constraints on an axion-photon-dark photon coupling, which can be the leading coupling to dark sector models and can also lead to dramatic changes to axion cosmology. We show that the supernova bound on this coupling has two unusual features. One occurs because the scattering that leads to the trapping regime converts axions and dark photons into each other. Thus, if one of the two new particles is sufficiently massive, both production and scattering become suppressed and the bounds from bulk emission and trapped (area) emission both weaken exponentially and do not intersection The other unusual feature occurs because for light dark photons, longitudinal modes couple more weakly than transverse modes do. Since the longitudinal mode is more weakly coupled, it can still cause excessive cooling even if the transverse mode is trapped. Thus, the supernova constraints for massive dark photons look like two independent supernova bounds super-imposed on top of each other.

scholarly journals Astrophysical aspects of milli-charged dark matter in a Higgs–Stueckelberg model

2015 ◽  
Vol 30 (18) ◽  
pp. 1550089 ◽  
Author(s):  
A. L. dos Santos ◽  
D. Hadjimichef
Keyword(s):  
Dark Matter ◽  
Weakly Interacting Massive Particles ◽  
Dark Sector ◽  
Minimal Coupling ◽  
Astrophysical Application ◽  
Gauge Sector ◽  
Dark Photon ◽  
The Standard Model ◽  
Vector Bosons ◽  
The Impact

An extension of the Standard Model (SM) is studied, in which two new vector bosons are introduced, a first boson Z' coupled to the SM by the usual minimal coupling, producing an enlarged gauge sector in the SM. The second boson A' field, in the dark sector of the model, remains massless and originates a dark photon γ'. A hybrid mixing scenario is considered based on a combined Higgs and Stueckelberg mechanisms. In a Compton-like process, a photon scattered by a weakly interacting massive particles (WIMP) is converted into a dark photon. This process is studied, in an astrophysical application obtaining an estimate of the impact on stellar cooling of white dwarfs and neutron stars.

scholarly journals Dark scalars and heavy neutral leptons at DarkQuest

2021 ◽  
Vol 2021 (5) ◽  
Author(s):  
Brian Batell ◽  
Jared A. Evans ◽  
Stefania Gori ◽  
Mudit Rai
Keyword(s):  
Particle Production ◽  
Meson Production ◽  
Gluon Fusion ◽  
New Physics ◽  
Dark Sector ◽  
Hidden Sector ◽  
Detector Acceptance ◽  
Light Scalar ◽  
Near Term

Abstract The proposed DarkQuest beam dump experiment, a modest upgrade to the existing SeaQuest/SpinQuest experiment, has great potential for uncovering new physics within a dark sector. We explore both the near-term and long-term prospects for observing two distinct, highly-motivated hidden sector benchmark models: heavy neutral leptons and Higgs-mixed scalars. We comprehensively examine the particle production and detector acceptance at DarkQuest, including an updated treatment of meson production, and light scalar production through both bremsstrahlung and gluon-gluon fusion. In both benchmark models, DarkQuest will provide an opportunity to probe previously inaccessible interesting regions of parameter space on a fairly short timescale when compared to other proposed experiments.

scholarly journals The PADME Detector

2018 ◽  
Vol 170 ◽  
pp. 01007 ◽  
Author(s):  
Paola Gianotti
Keyword(s):  
Beam Energy ◽  
Positron Beam ◽  
Precise Determination ◽  
Final State ◽  
Missing Mass ◽  
Dark Photon ◽  
Key Points ◽  
Background Events

The PADME experiment, by using the positron beam of the Frascati laboratory, aims at searching for signals of a dark photon, A′ . It will evaluate the final state missing mass of the process e+ e- → A′ γ by knowing the beam energy and measuring the four-momentum of the ordinary recoil photon. The precise determination of this quantity, and the capability to reject background events, are the key points for the success of the experiment. In this paper a description of each component of the PADME detector is given.

scholarly journals Distribution of magnetic dipole strength — binning

2020 ◽  
Vol 29 (03) ◽  
pp. 2050014
Author(s):  
Arun Kingan ◽  
Mingyang Ma ◽  
Larry Zamick
Keyword(s):  
Magnetic Dipole ◽  
Single Point ◽  
Energy Interval ◽  
Final States ◽  
Dipole Strength ◽  
Initial State ◽  
Large Space ◽  
Exponential Trend ◽  
Magnetic Dipole Transitions ◽  
Single Formula

In previous papers, we examined the systematics of magnetic dipole transitions in a single [Formula: see text] shell. We here extend the study to large space calculations. We consider the nuclei [Formula: see text]Ti, [Formula: see text]Ti and [Formula: see text]Cr. In this paper, we focus on the [Formula: see text] strength as a function of excitation of energy. The initial state is the lowest [Formula: see text] state in a specified nucleus. The final states are [Formula: see text] [Formula: see text], all in one plot, and [Formula: see text] [Formula: see text] in another. The initial figures have points all over the map although there is a suggestion of an exponential trend. To reduce clutter, we perform binning operations in which the summed strength in a given energy interval is represented by a single point. The new binning curves show more clearly the exponential fall of [Formula: see text]’s with energy.

scholarly journals Observation of Ionization of Laser Excited Atoms by Synchrotron Radiation

1984 ◽  
Vol 86 ◽  
pp. 128-131
Author(s):  
J.M. Bizau ◽  
F. Wuilleumier ◽  
P. Gerard ◽  
P. Dhez ◽  
B. Carré ◽  
...  
Keyword(s):  
Synchrotron Radiation ◽  
Photoelectron Spectroscopy ◽  
Oscillator Strengths ◽  
Final States ◽  
Initial State ◽  
Final State ◽  
Core Electron ◽  
Output Mirror ◽  
Initial States ◽  
A New Technique

We have begun a program to measure oscillator strengths of autoionizing resonances that result from a transition in the VUV between a laser excited initial state and a final state in which a core electron is promoted. These measurements demonstrate a new technique to combine synchrotron radiation, laser pumping, and photoelectron spectroscopy.Measurements of the energy positions of autoionizing resonances have been honed to a fine art over the past 50 years. Total cross section measurements and the parameters that describe autoionizing resonances have been determined. Most of these studies have been made from the dipole allowed ground state. Recently autoionizing resonances have been observed from excited initial states and from ion initial states. We have heard several talks, at this meeting which described some of this type of research. In the measurements to be described in this paper, laser radiation is combined with synchrotron radiation, as shown schematicaly in Figure 1, to study the photoionization from excited initial states to continuum final states or to autoionizing final states. Continuum radiation from the Aneau de Collisions d’Orsay (ACO), which is installed at the Universite de Paris-Sud, in Orsay France, is monochromatized by a toroidal grating monochromator (TGM) and is focused by a toroidal output mirror on to a weakly collimated sodium beam emanating from a furnace mounted on the axis of a cylinderical mirror analyzer (CMA). This electron spectrometer is used to study the kinetic energy distribution of the ejected photoelectrons produced by the interaction of the photon beam with the focused synchrotron radiation.

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