New results on catalyzed BBN with a long-lived negatively-charged massive particle

It has been proposed that the apparent discrepancies between the inferred primordial abundances of 6Li and 7Li and the predictions of big bang nucleosynthesis (BBN) can be resolved by the existence of a negatively-charged massive unstable supersymmetric particle (X-) during the BBN epoch. Here, we present new BBN calculations with an X- particle utilizing an improved nuclear reaction network including captures of nuclei by the particle, nuclear reactions and beta-decays of normal nuclei and nuclei bound to the X- particles (X-nuclei), and new reaction rates derived from recent rigorous quantum many-body dynamical calculations. We find that this is still a viable model to explain the observed 6Li and 7Li abundances. However, contrary to previous results, neutral X-nuclei cannot significantly affect the BBN light-element abundances. We also show that with the new rates the production of heavier nuclei is suppressed and there is no signature on abundances of nuclei heavier than Be in the X--particle catalyzed BBN model as has been previously proposed. We also consider the version of this model whereby the X- particle decays into the present cold dark matter. We analyze the this paradigm in light of the recent constraints on the dark-matter mass deduced from the possible detected events in the CDMS-II experiment. We conclude that based upon the inferred range for the dark-matter mass, only X- decay via the weak interaction can achieve the desired 7Li destruction while also reproducing the observed 6Li abundance.Comment: 6 pages, 2 figure

Effect of Long-lived Strongly Interacting Relic Particles on Big Bang Nucleosynthesis

It has been suggested that relic long-lived strongly interacting massive particles (SIMPs, or $X$ particles) existed in the early universe. We study effects of such long-lived unstable SIMPs on big bang nucleosynthesis (BBN) assuming that such particles existed during the BBN epoch, but then decayed long before they could be detected. The interaction strength between an $X$ particle and a nucleon is assumed to be similar to that between nucleons. We then calculate BBN in the presence of the unstable neutral charged $X^0$ particles taking into account the capture of $X^0$ particles by nuclei to form $X$-nuclei. We also study the nuclear reactions and beta decays of $X$-nuclei. We find that SIMPs form bound states with normal nuclei during a relatively early epoch of BBN. This leads to the production of heavy elements which remain attached to them. Constraints on the abundance of $X^0$ particles during BBN are derived from observationally inferred limits on the primordial light element abundances. Particle models which predict long-lived colored particles with lifetimes longer than $\sim$ 200 s are rejected based upon these constraints.Comment: 19 pages, 4 figure

Big Bang Nucleosynthesis Constraints on Hadronically and Electromagnetically Decaying Relic Neutral Particles

Big Bang nucleosynthesis in the presence of decaying relic neutral particles is examined in detail. All non-thermal processes important for the determination of light-element abundance yields of 2H, 3H, 3He, 4He, 6Li, and 7Li are coupled to the thermonuclear fusion reactions to obtain comparatively accurate results. Predicted light-element yields are compared to observationally inferred limits on primordial light-element abundances to infer constraints on the abundances and properties of relic decaying particles with decay times in the interval 0.01 sec < tau < 10^(12) sec. Decaying particles are typically constrained at early times by 4He or 2H, at intermediate times by 6Li, and at large times by the 3He/2H ratio. Constraints are shown for a large number of hadronic branching ratios and decaying particle masses and may be applied to constrain the evolution of the early Universe.Comment: 24 pages (revtex), 11 figures, title changed, matches published versio

Big Bang Nucleosynthesis with Bound States of Long-lived Charged Particles

Charged particles (X) decaying after primordial nucleosynthesis are constrained by the requirement that their decay products should not change the light element abundances drastically. If the decaying particle is negatively charged (X-) then it will bind to the nuclei. We consider the effects of the decay of X when bound to Helium-4 and show that this will modify the Lithium abundances.Comment: 5 pages; v2: references added, figure caption corrected; v3: references adde

Strong Interactive Massive Particles from a Strong Coupled Theory

Minimal walking technicolor models can provide a nontrivial solution for cosmological dark matter, if the lightest technibaryon is doubly charged. Technibaryon asymmetry generated in the early Universe is related to baryon asymmetry and it is possible to create excess of techniparticles with charge (-2). These excessive techniparticles are all captured by $^4He$, creating \emph{techni-O-helium} $tOHe$ ``atoms'', as soon as $^4He$ is formed in Big Bang Nucleosynthesis. The interaction of techni-O-helium with nuclei opens new paths to the creation of heavy nuclei in Big Bang Nucleosynthesis. Due to the large mass of technibaryons, the $tOHe$ ``atomic'' gas decouples from the baryonic matter and plays the role of dark matter in large scale structure formation, while structures in small scales are suppressed. Nuclear interactions with matter slow down cosmic techni-O-helium in Earth below the threshold of underground dark matter detectors, thus escaping severe CDMS constraints. On the other hand, these nuclear interactions are not sufficiently strong to exclude this form of Strongly Interactive Massive Particles by constraints from the XQC experiment. Experimental tests of this hypothesis are possible in search for $tOHe$ in balloon-borne experiments (or on the ground) and for its charged techniparticle constituents in cosmic rays and accelerators. The $tOHe$ ``atoms'' can cause cold nuclear transformations in matter and might form anomalous isotopes, offering possible ways to exclude (or prove?) their existence.Comment: 41 pages, 4 figure

A Cosmological Model with Dark Spinor Source

In this paper, we discuss the system of Friedman-Robertson-Walker metric coupling with massive nonlinear dark spinors in detail, where the thermodynamic movement of spinors is also taken into account. The results show that, the nonlinear potential of the spinor field can provide a tiny negative pressure, which resists the Universe to become singular. The solution is oscillating in time and closed in space, which approximately takes the following form g_{\mu\nu}=\bar R^2(1-\delta\cos t)^2\diag(1,-1,-\sin^2r ,-\sin^2r \sin^2\theta), with $\bar R= (1\sim 2)\times 10^{12}$ light year, and $\delta=0.96\sim 0.99$. The present time is about $t\sim 18^\circ$.Comment: 13 pages, no figure, to appear in IJMP

Dark matter with invisible light from heavy double charged leptons of almost-commutative geometry?

A new candidate of cold dark matter arises by a novel elementary particle model: the almostcommutative AC-geometrical framework. Two heavy leptons are added to the Standard Model, each one sharing a double opposite electric charge and an own lepton flavor number The novel mathematical theory of almost-commutative geometry [1] wishes to unify gauge models with gravity. In this scenario two new heavy (m_L>100GeV), oppositely double charged leptons (A,C),(A with charge -2 and C with charge +2), are born with no twin quark companions. The model naturally involves a new U(1) gauge interaction, possessed only by the AC-leptons and providing a Coulomblike attraction between them. AC-leptons posses electro-magnetic as well as Z-boson interaction and, according to the charge chosen for the new U(1) gauge interaction, a new "invisible light" interaction. Their final cosmic relics are bounded into "neutral" stable atoms (AC) forming the mysterious cold dark matter, in the spirit of the Glashow's Sinister model. An (AC) state is reached in the early Universe along a tail of a few secondary frozen exotic components. They should be now here somehow hidden in the surrounding matter. The two main secondary manifest relics are C (mostly hidden in a neutral (Cee) "anomalous helium" atom, at a 10-8 ratio) and a corresponding "ion" A bounded with an ordinary helium ion (4He); indeed the positive helium ions are able to attract and capture the free A fixing them into a neutral relic cage that has nuclear interaction (4HeA).Comment: This paper has been merged with [astro-ph/0603187] for publication in Classical and Quantum Gravit

Improvement of microwave equipment excitation efficiency using methods of focused arrays

The problem of multielement excitation of exposed-type microwave equipment is studied. Optimization problem is formulated as amplitudes, phases and elements location definition to maximize the special efficiency criteria. Both coherent and noncoherent multielement excitation are considered. Substantial improvement of microwave field excitation can be achieved by proposed approach. A number of particular optimization procedures advantageous for practical use is presented