Abstract
The accurate evaluation of the nuclear reaction rates and
corresponding uncertainties is an essential requisite for a precise
determination of light nuclide primordial abundances. The recent
...measurement of the D(p, γ)
3
He radiative capture cross
section by the LUNA collaboration, with its order 3% error,
represents an important step in improving the theoretical prediction
for Deuterium produced in the early universe. In view of this recent
result, we present in this paper a full analysis of its abundance,
which includes a new critical study of the impact of the other two
main processes for Deuterium burning, namely the deuteron-deuteron
transfer reactions, D(d, p)
3
H and D(d, n)
3
He. In particular,
emphasis is given to the statistical method of analysis of
experimental data, to a quantitative study of the theoretical
uncertainties, and a comparison with similar studies presented in
the recent literature. We then discuss the impact of our study on
the concordance of the primordial nucleosynthesis stage with the
Planck experiment results on the baryon density Ω
b
h
2
and
the effective number of neutrino parameter M
eff
, as function of
the assumed value of the
4
He mass fraction Y
p
. While after the
LUNA results, the value of Deuterium is quite precisely fixed, and
points to a value of the baryon density in excellent agreement with
the Planck result, a combined analysis also including Helium leads
to two possible scenarios with different predictions for
Ω
b
h
2
and , depending on the value adopted for Y
p
from astrophysical measurements. We argue that new results on the
systematics and mean value of Y
p
in metallicity poor environments
would be of great importance in assessing the overall concordance of
the standard cosmological model.
Bounds on very low reheating scenarios after Planck de Salas, P. F.; Lattanzi, M.; Mangano, G. ...
Physical review. D, Particles, fields, gravitation, and cosmology,
12/2015, Letnik:
92, Številka:
12
Journal Article
Light elements were produced in the first few minutes of the Universe through a sequence of nuclear reactions known as Big Bang nucleosynthesis (BBN)
. Among the light elements produced during BBN
, ...deuterium is an excellent indicator of cosmological parameters because its abundance is highly sensitive to the primordial baryon density and also depends on the number of neutrino species permeating the early Universe. Although astronomical observations of primordial deuterium abundance have reached percent accuracy
, theoretical predictions
based on BBN are hampered by large uncertainties on the cross-section of the deuterium burning D(p,γ)
He reaction. Here we show that our improved cross-sections of this reaction lead to BBN estimates of the baryon density at the 1.6 percent level, in excellent agreement with a recent analysis of the cosmic microwave background
. Improved cross-section data were obtained by exploiting the negligible cosmic-ray background deep underground at the Laboratory for Underground Nuclear Astrophysics (LUNA) of the Laboratori Nazionali del Gran Sasso (Italy)
. We bombarded a high-purity deuterium gas target
with an intense proton beam from the LUNA 400-kilovolt accelerator
and detected the γ-rays from the nuclear reaction under study with a high-purity germanium detector. Our experimental results settle the most uncertain nuclear physics input to BBN calculations and substantially improve the reliability of using primordial abundances to probe the physics of the early Universe.
The PTOLEMY project aims to develop a scalable design for a Cosmic Neutrino Background (CNB) detector, the first of its kind and the only one conceived that can look directly at the image of the ...Universe encoded in neutrino background produced in the first second after the Big Bang. The scope of the work for the next three years is to complete the conceptual design of this detector and to validate with direct measurements that the non-neutrino backgrounds are below the expected cosmological signal. In this paper we discuss in details the theoretical aspects of the experiment and its physics goals. In particular, we mainly address three issues. First we discuss the sensitivity of PTOLEMY to the standard neutrino mass scale. We then study the perspectives of the experiment to detect the CNB via neutrino capture on tritium as a function of the neutrino mass scale and the energy resolution of the apparatus. Finally, we consider an extra sterile neutrino with mass in the eV range, coupled to the active states via oscillations, which has been advocated in view of neutrino oscillation anomalies. This extra state would contribute to the tritium decay spectrum, and its properties, mass and mixing angle, could be studied by analyzing the features in the beta decay electron spectrum.
We describe a program for computing the abundances of light elements produced during Big Bang Nucleosynthesis which is publicly available at
http://parthenope.na.infn.it/. Starting from nuclear ...statistical equilibrium conditions the program solves the set of coupled ordinary differential equations, follows the departure from chemical equilibrium of nuclear species, and determines their asymptotic abundances as function of several input cosmological parameters as the baryon density, the number of effective neutrino, the value of cosmological constant and the neutrino chemical potential. The program requires commercial NAG library routines.
Program title: PArthENoPE
Catalogue identifier: AEAV_v1_0
Program summary URL:
http://cpc.cs.qub.ac.uk/summaries/AEAV_v1_0.html
Program obtainable from: CPC Program Library, Queen's University, Belfast, N. Ireland
Licensing provisions: Standard CPC licence,
http://cpc.cs.qub.ac.uk/licence/licence.html
No. of lines in distributed program, including test data, etc.: 10 033
No. of bytes in distributed program, including test data, etc.: 46 002
Distribution format: tar.gz
Programming language: Fortran 77
Computer: PC-compatible running Fortran on Unix, MS Windows or Linux
Operating system: Windows 2000, Windows XP, Linux
Classification: 1.2, 1.9, 17.8
External routines: NAG Libraries
Nature of problem: Computation of yields of light elements synthesized in the primordial universe.
Solution method: BDF method for the integration of the ODEs, implemented in a NAG routine.
Running time: 90 sec with default parameters on a Dual Xeon Processor 2.4 GHz with 2 GB RAM.
Abstract
The PTOLEMY transverse drift filter is a new concept to
enable precision analysis of the energy spectrum of electrons near
the tritium
β
-decay endpoint. This paper details the
...implementation and optimization methods for successful operation of
the filter for electrons with a known pitch angle. We present the
first demonstrator that produces the required magnetic field
properties with an iron return-flux magnet. Two methods for the
setting of filter electrode voltages are detailed. The challenges of
low-energy electron transport in cases of low field are discussed,
such as the growth of the cyclotron radius with decreasing magnetic
field, which puts a ceiling on filter performance relative to fixed
filter dimensions. Additionally, low pitch angle trajectories are
dominated by motion parallel to the magnetic field lines and
introduce non-adiabatic conditions and curvature drift. To minimize
these effects and maximize electron acceptance into the filter, we
present a three-potential-well design to simultaneously drain the
parallel and transverse kinetic energies throughout the length of
the filter. These optimizations are shown, in simulation, to achieve
low-energy electron transport from a 1 T iron core (or 3 T
superconducting) starting field with initial kinetic energy of
18.6 keV drained to < 10 eV (< 1 eV) in about 80 cm. This
result for low field operation paves the way for the first
demonstrator of the PTOLEMY spectrometer for measurement of
electrons near the tritium endpoint to be constructed at the Gran
Sasso National Laboratory (LNGS) in Italy.
PArthENoPE reloaded Consiglio, R.; de Salas, P.F.; Mangano, G. ...
Computer physics communications,
December 2018, 2018-12-00, Letnik:
233
Journal Article
Recenzirano
We describe the main features of a new and updated version of the program PArthENoPE, which computes the abundances of light elements produced during Big Bang Nucleosynthesis. As the previous first ...release in 2008, the new one, PArthENoPE2.0, is publicly available and distributed from the code site, http://parthenope.na.infn.it. Apart from minor changes, which will be also detailed, the main improvements are as follows. The powerful, but not freely accessible, NAG routines have been substituted by ODEPACK libraries, without any significant loss in precision. Moreover, we have developed a Graphical User Interface (GUI) which allows a friendly use of the code and a simpler implementation of running for grids of input parameters.
Program Title:PArthENoPE2.0
Program Files doi:http://dx.doi.org/10.17632/wvgr7d8yt9.1
Licensing provisions: GPLv3
Programming language: Fortran 77 and Python
Supplementary material: User Manual available on the web page http://parthenope.na.infn.it
Journal reference of previous version: Comput. Phys. Commun. 178 (2008) 956-971
Does the new version supersede the previous version?: Yes
Reasons for the new version: Make the code more versatile and user friendly
Summary of revisions: (1) Publicly available libraries (2) GUI for configuration
Nature of problem: Computation of yields of light elements synthesized in the primordial universe
Solution method: Livermore Solver for Ordinary Differential Equations (LSODE) for stiff and nonstiff systems
Ultra high energy neutrinos are produced by the interaction of hadronic cosmic rays with the cosmic radiation background. More exotic scenarios like
topological defects or
new hadrons predict even ...larger fluxes. In particular, Earth-skimming tau neutrinos could be detected by the fluorescence detector (FD) of Pierre Auger Observatory. A detailed evaluation of the expected number of events has been performed for a wide class of neutrino flux models. An updated computation of the neutrino-nucleon cross section and of the tau energy losses has been carried out. For the most optimistic theoretical models, about one Earth-skimming neutrino event is expected in several years at FD.
PArthENoPE revolutions Gariazzo, S.; F. de Salas, P.; Pisanti, O. ...
Computer physics communications,
02/2022, Letnik:
271
Journal Article
Recenzirano
Odprti dostop
This paper presents the main features of a new and updated version of the program PArthENoPE, which the community has been using for many years for computing the abundances of light elements produced ...during Big Bang Nucleosynthesis. This is the third release of the PArthENoPE code, after the 2008 and the 2018 ones, and will be distributed from the code's website, http://parthenope.na.infn.it. Apart from minor changes, the main improvements in this new version include a revisited implementation of the nuclear rates for the most important reactions of deuterium destruction, 2H(p,γ)3He, 2H(d, n)3He and 2H(d, p)3H, and a re-designed GUI, which extends the functionality of the previous one. The new GUI, in particular, supersedes the previous tools for running over grids of parameters with a better management of parallel runs, and it offers a brand-new set of functions for plotting the results.
Program title:PArthENoPE 3.0
CPC Library link to program files:https://doi.org/10.17632/wvgr7d8yt9.2
Developer's repository link:http://parthenope.na.infn.it
Licensing provisions: GPLv3
Programming language: Fortran 77 and Python
Nature of problem: Computation of yields of light elements synthesized in the primordial universe
Solution method: Livermore Solver for Ordinary Differential Equations (LSODE) for stiff and nonstiff systems, Python GUI for running and plotting
Journal reference of previous version: Comput. Phys. Commun. 233 (2018) 237-242
Does the new version supersede the previous version?: Yes
Reasons for the new version: Update of the physics and improvements in the GUI
Summary of revisions: Update of the physics implemented in the Fortran code and improvements in the GUI functionalities, in particular new plotting functions
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