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=== Astrophysical solutions ===
Considering the possibility that BBN predictions are sound, the measured value of the primordial Lithiumlithium abundance should be in error and astrophysical solutions offer revision to it. For example, systematic errors, including ionization correction and inaccurate stellar temperatures determination could affect Li/H ratios in stars. Furthermore, more observations on Lithiumlithium depletion remain important since present Lithiumlithium levellevels might not reflect the initial abundance in the star. In summary, accurate measurements of the primordial Lithiumlithium abundance is the current focus of progress, and it could be possible that the final answer does not lie in astrophysical solutions.<ref name="fields11" />
=== Nuclear physics solutions ===
NowWhen considerone considers the possibility that the measured primordial Lithium abundance is correct and based on the [[Standard Model]] of particle physics and the standard cosmology, then the Lithiumlithium problem implies errors in the BBN light element predictions. Although standard BBN rests on well-determined physics, the weak and strong interactions are complicated for BBN and therefore might be the weak point in standard BBN calculation.<ref name="fields11" />
FirstFirstly, reactions missingincorrect or incorrectmissing reactions could leadgive rise to Lithiumthe lithium problem. For incorrect reactions, major thoughts lie within revision to [[cross- section (physics)|cross section]] errors and standard thermonuclear rates according to recent studies.<ref>{{Cite journal|last=Angulo|first=C.|last2=Casarejos|first2=E.|last3=Couder|first3=M.|last4=Demaret|first4=P.|last5=Leleux|first5=P.|last6=Vanderbist|first6=F.|last7=Coc|first7=A.|last8=Kiener|first8=J.|last9=Tatischeff|first9=V.|last10=Davinson|first10=T.|last11=Murphy|first11=A. S.|date=September 2005|title=The 7Be(d,p)2α Cross Section at Big Bang Energies and the Primordial 7Li Abundance|url=https://ui.adsabs.harvard.edu/abs/2005ApJ...630L.105A/abstract|journal=ApJL|language=en|volume=630|issue=2|pages=L105–L108|doi=10.1086/491732|issn=0004-637X}}</ref><ref>{{Cite journal|last=Boyd|first=Richard N.|last2=Brune|first2=Carl R.|last3=Fuller|first3=George M.|last4=Smith|first4=Christel J.|date=November 2010|title=New nuclear physics for big bang nucleosynthesis|url=https://ui.adsabs.harvard.edu/abs/2010PhRvD..82j5005B/abstract|journal=PhRvD|language=en|volume=82|issue=10|pages=105005|doi=10.1103/PhysRevD.82.105005|issn=1550-7998}}</ref>
Second, starting from [[Fred Hoyle]]'s great discovery of [[carbon-12]] resonance,a [[Resonance (particle physics)|resonance]] in [[carbon-12]], an important factor in the [[triple-alpha process]], resonance reactions, some of which might have evaded experimental detection or whose effects have been underestimated, become possible solutions to the Lithiumlithium problem and are studied by many recently.<ref>{{Cite journal|last=Hammache|first=F.|last2=Coc|first2=A.|last3=de Séréville|first3=N.|last4=Stefan|first4=I.|last5=Roussel|first5=P.|last6=Ancelin|first6=S.|last7=Assié|first7=M.|last8=Audouin|first8=L.|last9=Beaumel|first9=D.|last10=Franchoo|first10=S.|last11=Fernandez-Dominguez|first11=B.|date=December 2013|title=Search for new resonant states in 10C and 11C and their impact on the cosmological lithium problem|url=https://ui.adsabs.harvard.edu/abs/2013PhRvC..88f2802H/abstract|journal=PhRvC|language=en|volume=88|issue=6|pages=062802|doi=10.1103/PhysRevC.88.062802|issn=0556-2813}}</ref><ref>{{Cite journal|last=O'Malley|first=P. D.|last2=Bardayan|first2=D. W.|last3=Adekola|first3=A. S.|last4=Ahn|first4=S.|last5=Chae|first5=K. Y.|last6=Cizewski|first6=J. A.|last7=Graves|first7=S.|last8=Howard|first8=M. E.|last9=Jones|first9=K. L.|last10=Kozub|first10=R. L.|last11=Lindhardt|first11=L.|date=October 2011|title=Search for a resonant enhancement of the 7Be + d reaction and primordial 7Li abundances|url=https://ui.adsabs.harvard.edu/abs/2011PhRvC..84d2801O/abstract|journal=PhRvC|language=en|volume=84|issue=4|pages=042801|doi=10.1103/PhysRevC.84.042801|issn=0556-2813}}</ref>
All these nuclear physics solutions are accessible in experimental validation, which make them highly possible resulted in a true answer.
=== Solutions beyond the standard model ===
Under the assumptions of all correct calculation, solutions [[beyond the standard model|beyond]] the existing [[Standard Model]] or standard cosmology might be needed.<ref name="fields11" />
Dark Mattermatter Decaydecay and [[Supersymmetrysupersymmetry]] provide one possibility, in which decaying dark matter scenarios introduce a rich array of novel processes that can alter light elements during and after BBN, and find the well-motivated origin in supersymmetric cosmologies. With the fully operational [[Large Hadron Collider|LHC]] (LHC), much of minimal supersymmetry lies within reach, which would revolutionize particle physics and cosmology if discovered.<ref name="fields11" />
Changing Fundamental[[fundamental Constantsconstants]] can be one possible solution, and it implies that first, atomic transitions in metals residing in high-[[redshift]] regions might behave differently from our own;. secondAdditionally, Standard Model couplings and particle masses might vary; third, variation in nuclear physics parameters is needed.<ref name="fields11" />
Nonstandard Cosmologiescosmologies indicate variation of the baryon to photon ratio in different regions. One proposal is a result of large-scale inhomogeneities in cosmic density, different from homogeneity defined in the [[cosmological principle]]. However, this possibility requires a large amount of observations to test it.<ref>{{Cite journal|last=Holder|first=Gilbert P.|last2=Nollett|first2=Kenneth M.|last3=van Engelen|first3=Alexander|date=June 2010|title=On Possible Variation in the Cosmological Baryon Fraction|url=https://ui.adsabs.harvard.edu/abs/2010ApJ...716..907H/abstract|journal=ApJ|language=en|volume=716|issue=2|pages=907–913|doi=10.1088/0004-637X/716/2/907|issn=0004-637X}}</ref>
==See also==
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