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Nuclear data explorer · reaction

7Li(p,α)4He

All 67 EXFOR datasets of this reaction: who measured it, where and when, what they measured and over which energies.

Gamow window and the gap

Every dataset EXFOR holds for this reaction, drawn by the energies it covers, against the energies a star uses.

67 datasets in 40 EXFOR entries, 1938–2025 · 2 without an energy range, not drawn

centre of the Sun, T₉ = 0.0157 (15.7 MK)

Lowest energy in EXFOR
10.1 keV
Schroeder et al., 1989 · S · A1291.005
Distance from the Gamow peak
Inside the window
E₀ = 15.3 keV, window 10–20.5 keV
Rate from energies not in EXFOR
3.3%
at T₉ = 0.0157, smooth estimate · 3.3% of it lies below the lowest energy in EXFOR
1 keV10 keV100 keV1 MeV10 MeV100 MeVCentre-of-mass energy (keV)E₀ = 15.3 keVσSσ→Eₓdσ/dΩAyYotherlowest in EXFOR 10.1 keV
  • Gamow window, hatched where no measurement reaches
  • Outlined bars are shown but not counted (the rule is under “How these numbers are made”).
  • A diamond is a dataset at a single energy. Bars running off the right edge continue to higher energies.
The datasets of the gap map, by quantity
The datasets of the gap map, by quantity
QuantityDatasetsE_cm range (keV)
σcross section138.74 keV – 10.5 MeV
SS-factor108.8 keV – 1.52 MeV
σ→Eₓpartial1370 keV – 2.1 MeV
dσ/dΩangular distribution3520.7 keV – 19.2 MeV
Aypolarization17.87 MeV – 19.2 MeV
Yyield319.7 keV – 887 keV
…other276 keV – 6.87 MeV
How these numbers are made

Lowest measured energy, everywhere in the data explorer: the lowest centre-of-mass energy at which a dataset in EXFOR measures the reaction itself (cross section, S-factor, angular distribution, yield or resonance strength), judged point by point. A point counts when it is a value, not an upper or lower limit, when it lies at least one standard deviation above zero, and when its energy is physical: at least 1 keV for charged particles, and not below the threshold of an endothermic reaction. Not counted: extrapolated, calculated, evaluated or derived values; superseded, deleted or preliminary data; ratios; a single S-factor value, which in EXFOR is a fit result; and indirect methods (Trojan horse, Coulomb dissociation, ANC, surrogate reactions), recognized from EXFOR's method and analysis codes, their text and the title. Frame and unit errors of EXFOR are corrected first, and values the literature shows to be upper limits are read as limits, from a list that gives the evidence for each. Datasets that reach the same energy within 0.5% are all credited, earliest first. Rate from energies not in EXFOR: the share of the rate integrand at that temperature outside the energy ranges the counted datasets cover (from their lowest measured point to their highest), with a constant S-factor (σ ∝ S(E₀)/E · e^−2πη, so the integrand is e^(−E/kT − 2πη)); for a neutron capture, σ ∝ 1/v. Resonances make the real integrand lumpy, so read it as a smooth baseline.

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