2,574 research outputs found
Phenomenology of left-right symmetric dark matter
We present a detailed study of dark matter phenomenology in low-scale
left-right symmetric models. Stability of new fermion or scalar multiplets is
ensured by an accidental matter parity that survives the spontaneous symmetry
breaking of the gauge group by scalar triplets. The relic abundance of these
particles is set by gauge interactions and gives rise to dark matter candidates
with masses above the electroweak scale. Dark matter annihilations are thus
modified by the Sommerfeld effect, not only in the early Universe, but also
today, for instance, in the Center of the Galaxy. Majorana candidates -
triplet, quintuplet, bi-doublet, and bi-triplet - bring only one new parameter
to the model, their mass, and are hence highly testable at colliders and
through astrophysical observations. Scalar candidates - doublet and 7-plet, the
latter being only stable at the renormalizable level - have additional
scalar-scalar interactions that give rise to rich phenomenology. The particles
under discussion share many features with the well-known candidates wino,
Higgsino, inert doublet scalar, sneutrino, and Minimal Dark Matter. In
particular, they all predict a large gamma-ray flux from dark matter
annihilations, which can be searched for with Cherenkov telescopes. We
furthermore discuss models with unequal left-right gauge couplings, , taking the recent experimental hints for a charged gauge boson with 2 TeV
mass as a benchmark point. In this case, the dark matter mass is determined by
the observed relic density.Comment: 32 + 23 pages, 4.5 MB; Minor changes and additional comments. Matches
published versio
Core formation from self-heating dark matter
Cosmological simulations of the CDM model suggest that the dark
matter halos of dwarf galaxies are denser in their center than what
observational data of such galaxies imply. In this letter, we propose a novel
solution to this problem by invoking a certain class of dark matter
self-heating processes. As we will argue, such processes lead to the formation
of dark matter cores at late times by considerably reducing the inner mass
density of dwarf-sized halos. For deriving concrete results, we focus on
semi-annihilating dark matter scenarios and model the inner region of dark
matter halos as a gravothermal fluid. An important aspect of this new solution
is that the semi-annihilation effects are much more prominent in dwarf-sized
halos than in the more massive halos that host galaxies and clusters, even if
the corresponding cross sections are the same. Furthermore, the preferred
parameter space for solving the small-scale problem suggests a thermal dark
matter candidate with a mass below the GeV scale, which can be probed in dark
matter direct and indirect detection experiments.Comment: Published version. 9 pages, 7 figure
Self-interacting Spin-2 Dark Matter
Recent developments in bigravity allow one to construct consistent theories
of interacting spin-2 particles that are free of ghosts. In this framework, we
propose an elementary spin-2 dark matter candidate with a mass well below the
TeV scale. We show that, in a certain regime where the interactions induced by
the spin-2 fields do not lead to large departures from the predictions of
general relativity, such a light dark matter particle typically self-interacts
and undergoes self-annihilations via 3-to-2 processes. We discuss its
production mechanisms and also identify the regions of the parameter space
where self-interactions can alleviate the discrepancies at small scales between
the predictions of the collisionless dark matter paradigm and cosmological
N-body simulations.Comment: Minor changes. It matches the published versio
Indirect searches of dark matter via polynomial spectral features
We derive the spectra arising from non-relativistic dark matter annihilations
or decays into intermediary particles with arbitrary spin, which subsequently
produce neutrinos or photons via two-body decays. Our approach is model
independent and predicts spectral features restricted to a kinematic box. The
overall shape within that box is a polynomial determined by the polarization of
the decaying particle. We illustrate our findings with two examples. First,
with the neutrino spectra arising from dark matter annihilations into the
massive Standard Model gauge bosons. Second, with the gamma-ray and neutrino
spectra generated by dark matter annihilations into hypothetical massive spin-2
particles. Our results are in particular applicable to the 750 GeV diphoton
excess observed at the LHC if interpreted as a spin-0 or spin-2 particle
coupled to dark matter. We also derive limits on the dark matter annihilation
cross section into this resonance from the non-observation of the associated
gamma-ray spectral features by the H.E.S.S. telescope.Comment: 19 pages, modified title, added references, minor changes. To appear
in JCA
WIMP and SIMP Dark Matter from the Spontaneous Breaking of a Global Group
We propose and study a scalar extension of the Standard Model which respects
a symmetry remnant of the spontaneous breaking of a global
symmetry. Consequently, this model has a natural dark matter
candidate and a Goldstone boson in the physical spectrum. In addition, the
Higgs boson properties are changed with respect to the Standard Model due to
the mixing with a new particle. We explore regions in the parameter space
taking into account bounds from the measured Higgs properties, dark matter
direct detection as well as measurements of the effective number of neutrino
species before recombination. The dark matter relic density is determined by
three classes of processes: the usual self-annihilation, semi-annihilation and
purely dark matter processes. The latter has been subject of recent
interest leading to the so-called `Strongly Interacting Massive Particle'
(SIMP) scenario. We show under which conditions our model can lead to a
concrete realization of such scenario and study the possibility that the dark
matter self-interactions could address the small scale structure problems. In
particular, we find that in order for the SIMP scenario to work, the dark
matter mass must be in the range MeV, with the global symmetry energy
breaking scale in the TeV range.Comment: 28 pages, 17 artistic figures. Accepted for publication in JCA
Immune Response Modulation by Tumor-Secreted Glycosphingolipids
Although originally considered merely structural components of cellular membranes, glycosphingolipids (GSL) arenow recognized as having critical effects on cellular physiology, including proliferation, differentiation, viraltransformation and ontogenesis. In addition, a vast majority of human cancers have modified GSL compositioncompared to parental normal cells. These modifications may contribute to both tumor survival and exert strikingeffects on anti-tumor immunity. In this review, we discuss mechanisms of immune modulation by tumor-secreted GSL.Fil: Lardone, Ricardo Dante. John Wayne Cancer Institute at Providence Saint John’s Health Center. Santa Monica; Estados Unidos. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Centro de Investigaciones en Química Biológica de Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Centro de Investigaciones en Química Biológica de Córdoba; ArgentinaFil: Cely, Ingrid. John Wayne Cancer Institute at Providence Saint John’s Health Center. Santa Monica; Estados UnidosFil: Sieling, Peter A.. John Wayne Cancer Institute at Providence Saint John’s Health Center. Santa Monica; Estados UnidosFil: Lee, Delphine. John Wayne Cancer Institute at Providence Saint John’s Health Center. Santa Monica; Estados Unido
Hubungan antara Gaya Kepemimpinan Telling dengan Kepuasan Kerja Anggota Polri pada Bidang Profesi dan Pengamanan Polda Sumatera Selatan
Febrida C. 2021. The relationship between telling leadership style and job satisfaction of police members in the field of profession and security of the South Sumatra regional police. In: Herlinda S et al. (Eds.), Prosiding Seminar Nasional Lahan Suboptimal ke-9 Tahun 2021, Palembang 20 Oktober 2021. pp. 451-458. Palembang: Penerbit & Percetakan Universitas Sriwijaya (UNSRI). The relationship between the leadership style of telling and job satisfaction of Police members in the field of profession and security at the South Sumatra Regional Police has not been widely studied. The study aimed to empirically find out how big the relationship is between the leadership style of telling and job satisfaction of Police members in the field of profession and security at the South Sumatra Regional Police. The research method used empirical juridical approach with the type of field research. The leadership style of telling is a leadership style where superiors carry out one-way communication, superiors formulate and define the roles of subordinates and the decisions making is entirely the responsibility of the superiors. Job satisfaction is a positive feeling felt by Police members as a result of the compatibility between the expectations and reality of work in the form of work, promotions, salaries, superiors, and co-workers. The results of this study showed that there was a very significant positive relationship between the leadership style of telling and job satisfaction of Police members in the profession and security sector of the South Sumatra Regional Police (r = 0.3333; F = 9.223; p = 0.003 or p < 0.01). A significance value of 0.003 showed the significance at the 1% test level (p = 0.01). So, the higher the leadership style of telling is, the lower the job satisfaction will be, and the lower the leadership style of telling is, the higher the job satisfaction will be. It is suggested that one of the most important things for a Police organization having a highly competitive ability be the handling of human resources either from the leadership style of telling or from job satisfaction
- …