78 research outputs found
The Parametrized Post-Newtonian-Vainshteinian formalism
Light degrees of freedom that modify gravity on cosmological scales must be "screened" on solar system scales in order to be compatible with data. The Vainshtein mechanism achieves this through a breakdown of classical perturbation theory, as large interactions involving new degrees of freedom become important below the so-called Vainshtein radius. We begin to develop an extension of the Parameterized Post-Newtonian (PPN) formalism that is able to handle Vainshteinian corrections. We argue that theories with a unique Vainshtein scale must be expanded using two small parameters. In this Parameterized Post-Newtonian-Vainshteinian (PPNV) expansion, the primary expansion parameter that controls the PPN order is, as usual, the velocity v. The secondary expansion parameter, α, controls the strength of the Vainshteinian correction and is a theory-specific combination of the Schwarzschild radius and the Vainshtein radius of the source that is independent of its mass. We present the general framework and apply it to Cubic Galileon theory both inside and outside the Vainshtein radius. The PPNV framework can be used to determine the compatibility of such theories with solar system and other strong-field data
Analysis of DDM into Gamma Radiation
We are interested in the purpose of a dipolar fermionic particle as a viable candidate of Dark Matter (DDM). Then, we study the annihilation of dark matter into photons, considering it as a neutral particle with non-vanishing magnetic (M) and electric (D) dipolar moments. The total annihilation cross section σ(χ → γ) is computed by starting from a general form of coupling χγ in a framework beyond to Standard Model (BSM). We found that candidates with O(mχ )∽102GeV, D≈10−16 e cm are required in order to satisfy the current cosmic relic density
Antineutrino Geophysics with Liquid Scintillator Detectors
Detecting the antineutrinos emitted by the decay of radioactive elements in
the mantle and crust could provide a direct measurement of the total abundance
of uranium and thorium in the Earth. In calculating the antineutrino flux at
specific sites, the local geology of the crust and the background from the
world's nuclear power reactors are important considerations. Employing a global
crustal map, with type and thickness data, and using recent estimates of the
uranium and thorium distribution in the Earth, we calculate the antineutrino
event rate for two new neutrino detectors. We show that spectral features allow
terrestrial antineutrino events to be identified above reactor antineutrino
backgrounds and that the uranium and thorium contributions can be separately
determined.Comment: Published paper differs from original submitted preprint because
reviewers suggested updated continental crust U/Th abundances. Kamioka
geographical location error was in preprint, partially corrected in published
version. This version is the same as the published paper, with Kamioka fully
corrected. Because of recent interest in this topic, this version is being
made available, despite this work being 8 years ol
Discriminating among Earth composition models using geo-antineutrinos
It has been estimated that the entire Earth generates heat corresponding to
about 40 TW (equivalent to 10,000 nuclear power plants) which is considered to
originate mainly from the radioactive decay of elements like U, Th and K,
deposited in the crust and mantle of the Earth. Radioactivity of these elements
produce not only heat but also antineutrinos (called geo-antineutrinos) which
can be observed by terrestrial detectors. We investigate the possibility of
discriminating among Earth composition models predicting different total
radiogenic heat generation, by observing such geo-antineutrinos at Kamioka and
Gran Sasso, assuming KamLAND and Borexino (type) detectors, respectively, at
these places. By simulating the future geo-antineutrino data as well as reactor
antineutrino background contributions, we try to establish to which extent we
can discriminate among Earth composition models for given exposures (in units
of kt yr) at these two sites on our planet. We use also information on
neutrino mixing parameters coming from solar neutrino data as well as KamLAND
reactor antineutrino data, in order to estimate the number of geo-antineutrino
induced events.Comment: 24 pages, 10 figures, final version to appear in JHE
Earth Radioactivity Measurements with a Deep Ocean Anti-neutrino Observatory
We consider the detector size, location, depth, background, and radio-purity
required of a mid-Pacific deep-ocean instrument to accomplish the twin goals of
making a definitive measurement of the electron anti-neutrino flux due to
uranium and thorium decays from Earth's mantle and core, and of testing the
hypothesis for a natural nuclear reactor at the core of Earth. We take the
experience with the KamLAND detector in Japan as our baseline for sensitivity
and background estimates. We conclude that an instrument adequate to accomplish
these tasks should have an exposure of at least 10 kilotonne-years (kT-y),
should be placed at least at 4 km depth, may be located close to the Hawaiian
Islands (no significant background from them), and should aim for KamLAND
radio-purity levels, except for radon where it should be improved by a factor
of at least 100. With an exposure of 10 kT-y we should achieve a 24%
measurement of the U/Th content of the mantle plus core. Exposure at multiple
ocean locations for testing lateral heterogeneity is possible.Comment: 15 pages, 1 figure, submitted to Earth, Moon, and Planets, Special
Issue Neutrino Geophysic
Proton-proton scattering above 3 GeV/c
A large set of data on proton-proton differential cross sections, analyzing
powers and the double polarization parameter A_NN is analyzed employing the
Regge formalism. We find that the data available at proton beam momenta from 3
GeV/c to 50 GeV/c exhibit features that are very well in line with the general
characteristics of Regge phenomenology and can be described with a model that
includes the rho, omega, f_2, and a_2 trajectories and single Pomeron exchange.
Additional data, specifically for spin-dependent observables at forward angles,
would be very helpful for testing and refining our Regge model.Comment: 16 pages, 19 figures; revised version accepted for publication in
EPJ
Charged Kaon K \to 3 pi CP Violating Asymmetries at NLO in CHPT
We give the first full next-to-leading order analytical results in Chiral
Perturbation Theory for the charged Kaon K \to 3 pi slope g and decay rates
CP-violating asymmetries. We have included the dominant Final State
Interactions at NLO analytically and discussed the importance of the unknown
counterterms. We find that the uncertainty due to them is reasonable just for
\Delta g_C, i.e. the asymmetry in the K^+ \to pi^+ pi^+ pi^- slope g; we get
\Delta g_C = -(2.4 +- 1.2) 10^{-5}. The rest of the asymmetries are very
sensitive to the unknown counterterms. In particular, the decay rate
asymmetries can change even sign. One can use this large sentivity to get
valuable information on those counterterms and on Im(G_8) coupling --very
important for the CP-violating parameter epsilon'_K-- from the eventual
measurement of these asymmetries. We also provide the one-loop O(e^2 p^2)
electroweak octet contributions for the neutral and charged Kaon K \to 3 pi
decays.Comment: 43+2 pages, 2 figures. Version accepted in JHEP. Small changes in the
final numerics of CP asymmetries due to change in input valu
- …