Refined scenario of standard Big Bang nucleosynthesis allowing for nonthermal nuclear reactions in the primordial plasma

2012 ◽  
Author(s):  
Victor T. Voronchev ◽  
Yasuyuki Nakao ◽  
Makoto Nakamura ◽  
Kazuki Tsukida
Keyword(s):  
Nuclear Reactions ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Primordial Plasma

EFFECT OF NEGATIVELY-CHARGED MASSIVE PARTICLES ON BIG-BANG NUCLEOSYNTHESIS AND A SOLUTION TO THE LITHIUM PROBLEMS

2008 ◽  
Vol 23 (17n20) ◽  
pp. 1668-1674
Author(s):  
MOTOHIKO KUSAKABE ◽  
TOSHITAKA KAJINO ◽  
RICHARD N. BOYD ◽  
TAKASHI YOSHIDA ◽  
GRANT J. MATHEWS
Keyword(s):  
Charged Particle ◽  
Nuclear Reactions ◽  
Charged Particles ◽  
Big Bang ◽  
Light Nuclei ◽  
Big Bang Nucleosynthesis ◽  
Spectroscopic Observations ◽  
Halo Stars ◽  
Wmap Data ◽  
Ionization Processes

Spectroscopic observations of metal poor halo stars give an indication of a possible primordial plateau of 6 Li abundance as a function of metallicity similar to that for 7 Li . The inferred abundance of 6 Li is ~1000 times larger than that predicted by standard big bang nucleosynthesis (BBN) for the baryon-to-photon ratio inferred from the WMAP data, and that of 7 Li is about 3 times smaller than the prediction. We study a possible solution to both the problems of underproduction of 6 Li and overproduction of 7 Li in BBN. This solution involves a hypothetical massive, negatively-charged particle that would bind to the light nuclei produced in BBN. The particle gets bound to the existing nuclei after the usual BBN, and a second epoch of nucleosynthesis can occur among nuclei bound to the particles. We numerically carry out a fully dynamical BBN calculation, simultaneously solving the recombination and ionization processes of negatively-charged particles by normal and particle-bound nuclei as well as many possible nuclear reactions among them. It is confirmed that BBN in the presence of these hypothetical particles can solve the two Li abundance problems simultaneously.

STAU-CATALYZED BIG-BANG NUCLEOSYNTHESIS AND NUCLEAR CLUSTER MODEL

2009 ◽  
Vol 24 (11) ◽  
pp. 2076-2083 ◽  
Author(s):  
M. KAMIMURA ◽  
Y. KINO ◽  
E. HIYAMA
Keyword(s):  
Cross Sections ◽  
Cluster Model ◽  
Nuclear Reactions ◽  
Light Element ◽  
Bound State ◽  
Big Bang ◽  
Reaction Cross ◽  
Big Bang Nucleosynthesis ◽  
Model Calculations ◽  
Three Body

Three-body cluster-model calculations are performed for the new types of big-bang nucleosynthesis (BBN) reactions that are calalyzed by a supersymmetric (SUSY) particle stau, a scalar partner of the tau lepton. If a stau has a lifetime ≳ 103s, it would capture a light element previously synthesized in standard BBN and form a Coulombic bound state. The bound state, an exotic atom, is expected to induce various reactions, such as (αX-) + d → 6 Li + X-, in which a negatively charged stau (denoted as X-) works as a catalyzer. Recent literature papers have claimed that some of these stau-catalyzed reactions have significantly large cross sections so that inclusion of the reactions into the BBN network calculation can change drastically abundances of some elements, giving not only a solution to the 6 Li -7 Li problem (calculated underproduction of 6 Li by ~ 1000 times and overproduction of 7 Li +7 Be by ~ 3 times) but also a constraint on the lifetime and the primordial abundance of the elementary particle stau. However, most of these literature calculations of the reaction cross sections were made assuming too naive models or approximations that are unsuitable for those complicated low-energy nuclear reactions. We use a few-body calculational method developed by the authors, and provides precise cross sections and rates of the stau-catalyzed BBN reactions for the use in the BBN network calculation.

scholarly journals Big Bang nucleosynthesis with long-lived strongly interacting relic particles

2009 ◽  
Vol 5 (S268) ◽  
pp. 33-38
Author(s):  
Motohiko Kusakabe ◽  
Toshitaka Kajino ◽  
Takashi Yoshida ◽  
Grant J. Mathews
Keyword(s):  
Beta Decay ◽  
Bound States ◽  
Nuclear Reactions ◽  
Interaction Strength ◽  
Light Element ◽  
Big Bang ◽  
Heavy Elements ◽  
Big Bang Nucleosynthesis ◽  
Element Abundances ◽  
Strongly Interacting

AbstractWe study effects of relic long-lived strongly interacting massive particles (X particles) on big bang nucleosynthesis (BBN). The X particle is assumed to have existed during the BBN epoch, but decayed long before detected. The interaction strength between an X and a nucleon is assumed to be similar to that between nucleons. Rates of nuclear reactions and beta decay of X-nuclei are calculated, and the BBN in the presence of neutral charged X0 particles is calculated taking account of captures of X0 by nuclei. As a result, the X0 particles form bound states with normal nuclei during a relatively early epoch of BBN leading to the production of heavy elements. Constraints on the abundance of X0 are derived from observations of primordial light element abundances. Particle models which predict long-lived colored particles with lifetimes longer than ~200 s are rejected. This scenario prefers the production of 9Be and 10B. There might, therefore, remain a signature of the X particle on primordial abundances of those elements. Possible signatures left on light element abundances expected in four different models are summarized.

scholarly journals Nuclear Astrophysics Deep Underground

2018 ◽  
Vol 46 ◽  
pp. 1860003 ◽  
Author(s):  
Rosanna Depalo
Keyword(s):  
Cross Sections ◽  
Nuclear Reactions ◽  
Nuclear Astrophysics ◽  
Cosmic Ray ◽  
Big Bang ◽  
Big Bang Nucleosynthesis ◽  
Present Contribution ◽  
Hydrogen Burning ◽  
The Earth ◽  
Deep Underground

Cross sections of nuclear reactions relevant for astrophysics are crucial ingredients to understand the energy generation inside stars and the synthesis of the elements. At astrophysical energies, nuclear cross sections are often too small to be measured in laboratories on the Earth surface, where the signal would be overwhelmed by the cosmic-ray induced background. LUNA is a unique Nuclear Astrophysics experiment located at Gran Sasso National Laboratories. The extremely low background achieved at LUNA allows to measure nuclear cross sections directly at the energies of astrophysical interest. Over the years, many crucial reactions involved in stellar hydrogen burning as well as Big Bang nucleosynthesis have been measured at LUNA. The present contribution provides an overview on underground Nuclear Astrophysics as well as the latest results and future perspectives of the LUNA experiment.

scholarly journals Dark matter dilution scenarios in the early universe

2021 ◽  
Author(s):  
Arnab Chaudhuri ◽  
Maxim Yu. Khlopov
Keyword(s):  
Phase Transition ◽  
Dark Matter ◽  
Early Universe ◽  
Small Mass ◽  
Big Bang ◽  
Primordial Black Holes ◽  
Big Bang Nucleosynthesis ◽  
Electroweak Phase Transition ◽  
Primordial Plasma ◽  
The Standard Model

When the vacuum like energy of the Higgs potential within the standard model undergoes electroweak phase transition, an influx of entropy into the primordial plasma can lead to a significant dilution of frozen out dark matter density that was already present before the onset of the phase transition. The same effect can take place if the early universe was dominated by primordial black holes of small mass, evaporating before the period of Big Bang Nucleosynthesis. In this paper, we calculate the dilution factor for the above-mentioned scenarios.

scholarly journals A solution to lithium problem by long-lived stau

2017 ◽  
Vol 26 (08) ◽  
pp. 1741005 ◽  
Author(s):  
Joe Sato ◽  
Takashi Shimomura ◽  
Masato Yamanaka
Keyword(s):  
Parameter Space ◽  
Internal Conversion ◽  
Nuclear Reactions ◽  
Bound State ◽  
Big Bang ◽  
Supersymmetric Particle ◽  
Relevant Parameter ◽  
Light Elements ◽  
Big Bang Nucleosynthesis ◽  
Supersymmetric Partner

We review a nonstandard Big-Bang Nucleosynthesis (BBN) scenario within the minimal supersymmetric standard model, and propose an idea to solve both the [Formula: see text] and [Formula: see text] problems. Each problem is a discrepancy between the predicted abundance in the standard BBN and observed one. We focus on the stau, a supersymmetric partner of tau lepton, which is a long-lived charged particle when it is the next lightest supersymmetric particle and is degenerate in mass with the lightest supersymmetric particle. The long-lived stau forms a bound state with a nucleus, and provides nonstandard nuclear reactions. One of those, the internal conversion process, accelerates the destruction of [Formula: see text] and [Formula: see text], and leads to a solution to the [Formula: see text] problem. On the other hand, the bound state of the stau and [Formula: see text] enhances productions of n, D, T and [Formula: see text]. The over-production of [Formula: see text] could solve the [Formula: see text] problem; while the over-productions of D and T could conflict with observations, and hence the relevant parameter space of the stau is strictly constrained. We therefore need to carefully investigate the stau–[Formula: see text] bound state to find a condition of solving the [Formula: see text] problem. The scenario of the long-lived stau simultaneously and successfully fits the abundances of light elements (D, T, [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text]) and the neutralino dark matter to the observed ones. Consequently, the parameter space both of the stau and the neutralino is determined with excellent accuracy.

scholarly journals Introduction to big bang nucleosynthesis and modern cosmology

2017 ◽  
Vol 26 (08) ◽  
pp. 1741001 ◽  
Author(s):  
Grant J. Mathews ◽  
Motohiko Kusakabe ◽  
Toshitaka Kajino
Keyword(s):  
Nuclear Reactions ◽  
Big Bang ◽  
Cosmological Models ◽  
Big Bang Nucleosynthesis ◽  
Primordial Nucleosynthesis ◽  
Current State ◽  
Modern Cosmology ◽  
Basic Equations ◽  
The Big Bang ◽  
The Universe

Primordial nucleosynthesis remains as one of the pillars of modern cosmology. It is the testing ground upon which many cosmological models must ultimately rest. It is our only probe of the universe during the important radiation-dominated epoch in the first few minutes of cosmic expansion. This paper reviews the basic equations of space-time, cosmology, and big bang nucleosynthesis. We also summarize the current state of observational constraints on primordial abundances along with the key nuclear reactions and their uncertainties. We summarize which nuclear measurements are most crucial during the big bang. We also review various cosmological models and their constraints. In particular, we analyze the constraints that big bang nucleosynthesis places upon the possible time variation of fundamental constants, along with constraints on the nature and origin of dark matter and dark energy, long-lived supersymmetric particles, gravity waves, and the primordial magnetic field.

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