Early-Universe Nucleosynthesis  

In General > s.a. astrophysics; elements; nuclear physics; observational cosmology [chemistry].
* Idea: D, 3He, 4He and 7Li were synthesized in the first 1000 s; 1998, There is rough agreement between observation and theory for 3 light neutrinos and

Nnucleons / Nphotons = 3 to 4 × 10–10,

but some problems remain with 4He and D abundances; 2010, ..., 2014, There is a mismatch in the 7Li abundance.
* Time: One way to estimate when nucleosynthesis occurred is the "Thorium/Uranium chronometer" approach, which compares a calculated value of the initial Th/U ratio and the current abundance ratio, using their lifetimes.
@ Reviews: Turner NA-ap/96; Schramm & Turner RMP(98); Olive ap/00-talk; Steigman EAA(00)ap-en; Dolgov NPPS(02)hp; Steigman ap/02-ln, ap/03-ch; Steigman ARNPS(07)-a0712; Miele & Pisanti NPPS(09)-a0811; Iocco et al PRP(09); Cyburt et al RMP(16)-a1505; Coc JPCS(16)-a1609.
@ General references: Alpher et al PR(48) [the paper that started it all]; Hogan SA(96)dec [deuterium]; Esposito et al NPB(00)ap/99, NPPS(00)ap/99; Olive ap/02-ln; Harwit & Spaans ApJ(03)ap; Molaro a0708-talk; Nollett pw(07)aug; Niu et al PRC(09) [Th/U chronometer]; Moriya & Shigeyama PRD(10)-a1001 [inhomogeneous nucleosynthesis]; Glover IAU(11)-a1107 [early-universe chemistry]; Kusakabe et al ApJ(14)-a1403 [effects of a long-lived negatively charged massive particle].

Special Topics > s.a. Nitrogen.
* Lithium-7 problem: A discrepancy between the predicted standard big-bang nucleosynthesis abundance of 7Li and its observational determination in metal-poor stars; The theoretical 7Li abundance is 3-4 times greater than the observational values, assuming the baryon-to-photon ratio determined by WMAP, and it appears difficult to adjust parameters in the theory to fix that without affecting other predictions; 2015, possible solution proposed by Poulin & Serpico based on a modified photon spectrum in electromagnetic cascades, with more high-energy photons.
@ Primordial deuterium: Di Valentino et al PRD(14)-a1404 [with Planck and BICEP2 data].
@ Primordial He: Peimbert et al ASP-ap/02; Salvaterra & Ferrara MNRAS(03)ap [vs population III stars]; Peimbert et al RMAA-a1608 [and the number of neutrino families]; > s.a. Helium.
@ Primordial Li: Jedamzik PRL(00) [6Li and exotic physics]; news pw(06)aug [fate of Li]; Pospelov PRL(07)hp/06, Bird et al PRD(08)-ap/07 + pn(07)may [formation catalyzed by charged particles]; Cumberbatch et al PRD(07)-a0708 [and late-decaying particles].
@ Lithium-7 problem: Fields ARNPS(11)-a1203; Regis & Clarkson GRG(12)-a1003 [and homogeneity]; Chakraborty et al PRD(11) [possible nuclear-physics resolution]; Broggini et al JCAP(12)-a1202 [nuclear-physics perspective]; Iocco MSAI-a1206-proc [phenomenologist's perspective]; news PhysOrg(12)sep [the mystery deepens]; Ouyed a1304 [proposed solution]; He et al a1412 [proposed solution using non-extensive Tsallis statistics]; Poulin & Serpico PRL(15) + news PhysOrg(15)mar [and electromagnetic cascades]; Goudelis et al PRL(16) + pw(16)jun [and light neutral particles]; Salvati et al JCAP(16)-a1606 [sterile neutrino solution]; > s.a. Lithium; standard cosmological problem / matter [mirror matter]; matter near black holes [lithium synthesis].
@ Other theories: Massó & Rota PRD(03) [modified Friedmann equation]; Mueller et al PRD(04)ap [varying constants]; Tian a1511 [in power-law f(R) gravity]; Capozziello et al a1702 [and constraints on f(T) teleparallel gravity]; > s.a. scalar-tensor gravity.
@ As probe of fundamental physics: Dent et al PRD(07)-a0705; > s.a. modified electromagnetism; lorentz violations; non-commutative geometry; quantum-gravity phenomenology.
@ Other related topics: Carroll & Kaplinghat PRD(02)ap/01 [and expansion]; Lara et al PRD(06) [inhomogeneous big bang]; Coc et al PRD(12)-a1206 [and variation of fundamental constants]; Hou et al a1408 [possible (Tsallis-type) deviations from Maxwell-Boltzmann velocity distribution for nuclei].

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