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The pp-chain and the CNO-cycle after KamLAND

The pp-chain and the CNO-cycle after KamLAND. Solar neutrinos after SNO and KamLAND The Boron flux The Beryllium flux Nuclear physics of the pp-chain Can the sun shine with CNO? New challenges for solar model builders The Sun as a laboratory for fundamental physics

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The pp-chain and the CNO-cycle after KamLAND

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  1. The pp-chain and the CNO-cycle after KamLAND • Solar neutrinos after SNO and KamLAND • The Boron flux • The Beryllium flux • Nuclear physics of the pp-chain • Can the sun shine with CNO? • New challenges for solar model builders • The Sun as a laboratory for fundamental physics Main message: accurate determinations of S17,S34 and S1,14 are particularly important now. GF and BR LNGS 21-02-03

  2. SNO: the appearance experiment • A 1000 tons heavy water detector sensitive to B-neutrinos by means of: • CC: ne+d -> p + p + e • sensitive to ne only, provides a good measurement of ne spectrum with weak directionality • NC: nx+d -> p + n + nx • Equal cross section for alln flavors. It measures the total 8B flux from Sun. • ES: nx+e -> e + nx • Mainly sensitive to ne, strong directionality. The important point is that SNO can determine both: F(ne) andF(ne + nm + nt )

  3. LMA SNO results • The measured total B neutrino flux is in excellent agreement with the SSM prediction: • About 2/3 of produced ne transform into nm and/or nt. • The large mixing angle (LMA) solution is preferred by a global fit of Chlorine, Gallium, SuperK and SNO data. (1s) (1s) LOW JUST-SO

  4. The first KamLAND results • Source: anti-ne from distant (»100 km) nuclear reactors • Detector: 1Kton liquid scintillator where: • Anti-ne +p -> n + e+ • n + p -> d + g • Measure the energy released in the slowing down and annihilation of e+ • Evis=T+2me in the presence of the 2MeV g ray. • Observed/Expected= 54/ (86+-5.5) • - >Oscillation of reactor anti-ne proven • Best fit : Dm2= 6.9 10-5 eV2 ; sin2 2q = 0.91 • - >LMA solution for solar neutrinos confirmed.

  5. LMA LOW Just-So The impact of KamLAND first results on solar neutrinos Before After LMA After KamLAND Dm2 is restricted to the region (5-20)10-5 eV2. Bahcall et al. hep-ph/0212147, Fogli et al. hep-ph/0212127 ….

  6. BrunoPontecorvo • Neutron Well Logging - A New Geological Method Based on Nuclear Physics, Oil and Gas Journal, 1941, vol.40, p.32-33.1942. • An application of Rome celebrated study on slow neutrons, the neutron log is an instrument sensitive to water and hydrocarbons. • It contains a (MeV) neutron source and a (thermal) neutron detector. As hydrogen atoms are by far the most effective in the slowing down of neutrons, the distribution of the neutrons at the time of detection is primarily determined by the hydrogen concentration, i.e. water and hydrocarbons. • The Cl-Ar method • Neutrino sources (sun, reactors, accelerators) • Neutrino oscillations

  7. From neutrons to neutrinos • We have learnt a lot on neutrinos. Their survival/transmutation probabilities in matter are now understood. • We have still a lot to learn for a precise description of the mass matrix (and other neutrino properties…) • Now that we know the fate of neutrinos, we can learn a lot from neutrinos.

  8. Neutrinos and Supernovae Neutrinos and the Earth Neutrino contribution to DM What next? Neutrinos and the Sun

  9. The measured boron flux • The total active FB=F(ne + nm + nt) boron flux is now a measured quantity. By combining all observational data one has*: FB= 5.05 (1 ± 0.06) 106 cm-2s-1. • The central value is in perfect agreement with the Bahcall 2000 SSM • Note the present1s error is DFB/FB =6% • In the next few yearsone can expect to reach DFB/FB»3% *Bahcall et al. hep-ph 0212147

  10. FB The Boron Flux, Nuclear Physics and Astrophysics s33s34s17se7spp Nuclear • FB depends on nuclear physics and astrophysics inputs • Scaling laws have been found numerically* and are physically understood FB= FB (SSM)· s33-0.43 s34 0.84 s171 se7-1 spp-2.7 · com1.4 opa2.6 dif 0.34 lum7.2 • These give flux variation with respect to the SSM calculation when the input X is changed by x = X/X(SSM) . • Can learn astrophysics if nuclear physics is known well enough. astro *Scaling laws derived from FRANEC models including diffusion. Coefficients closer to those of Bahcall are obtained if diffusion is neglected.

  11. Uncertainties budget • Nuclear physics uncertainties, particularly on S17 and S34 , dominate over the present observational accuracy DFB/FB =6%. • The foreseeable accuracy DFB/FB =3% could illuminate about solar physics if a significant improvement on S17 and S34 is obtained. • For fully exploiting the physics potential of a FB measurement with 3% accuracy one has to determine S17 and S34 at the level of 3% or better. • *LUNA gift • **Adelberger estimate: see below • ***by helioseismic const. • [gf et al.A&A 342 (1999) 492] • See similar table in JNB, astro-ph/0209080

  12. Progress on S17 • JNB and myself still use a conservative uncertainty (-2+4), however recently high accuracy determinations of S17 have appeared. • Average from 5 recent determinations yields: • S17(0)= 21.1 ± 0.4 with c2/dof=2 • If one omits Junghans et al.* one finds: • S17(0)= 20.5 ± 0.5 with c2/dof=1.2 • If we add in quadrature an “error in theory” of ± 0.5 we get a consistent common value: • S17(0)= 20.5 ± 0.7 eV b S17(0)[eV b] Data published Results of direct capture expts**. *”The cross section values of this paper are being revised” ( K.A. Snover, private communication). **See also Gialanella et al EPJ A7, 303 (2001)

  13. Comparison between most recent data 1)The lowest measured energies are about 200 and 300 keV 2)Theoretical extrapolations are important so far 3)It would be most helpful to lower the energy and see if and how the curve rises Junghans et al. Baby et al. S17(0)=22.3 ± 0.7 eV b S17(0)=21.2 ± 0.7 eV b DB theory NPA 567, 341(1994)

  14. Remark on S17 and S34 • If really S17(0)= 20.5 ± 0.7 eV bthis means a 3.5% accuracy. • The 9% error of S34 is the main source of uncertainty for extracting physics from Boron flux. • LUNA results on S34 will be extremely important.

  15. pp Be Fi/FiSSM B T/TSSM Sensitivity to the central temperature Castellani et al. ‘97 Bahcall and Ulmer. ‘96 • Boron neutrinos are mainly determined by the central temperature, almost in the way we vary it. • (The same holds for pp and Be neutrinos)

  16. The central solar temperature • The various inputs to FB can be grouped according to their effect on the solar temperature. • All nuclear inputs (but S11) only determine branches ppI/ppII/ppIII without changing solar structure. • The effect of the others can be reabsorbed into a variation of the “central” solar temperature: • FB =FB(SSM) [T /T(SSM) ]20. .S33-0.43 s340.84 s17 se7-1 • Boron neutrinos are excellent solar thermometers due to their high (»20) power dependence.

  17. Present and future for measuring T with B-neutrinos • At present, DFB/FB =6% and DSnuc/ Snuc= 13% (cons.) translate into DT/T= 0.7 % the main error being due to S17 and S34. • If nuclear physics were perfect (DSnuc/Snuc =0) already now we could have: DT/T= 0.3 % • When DFB/FB =3% one can hope to reach (for DSnuc/Snuc =0) : DT/T= 0.15 %

  18. Du/u 1s3s The central solar temperature and helioseismology • Helioseismology determines sound speed. • The accuracy on its square is Du/u • 0.15% inside the sun. • Accuracy of the helioseismic method degrades to 1% near the centre. • Boron neutrinos provide a complementary information, as they measure T. present DT/T future • For the innermost part, neutrinos are now (DT/T = 0.7%) almost as accurate as helioseismology • They can become more accurate than helioseismology in the future.

  19. The Sun as a laboratory for astrophysics and fundamental physics • A measurement of the solar temperature near the center with 0.15% accuracy can be relevant for many purposes • It provides a new challenge to SSM calculations • It allows a determination of the metal content in the solar interior, which has important consequences on the history of the solar system (and on exo-solar systems) • One can find constraints (surprises, or discoveries) on: • Axion emission from the Sun • The physics of extra dimensions (through Kaluza-Klein axion emission) • Dark matter (if trapped in the Sun it can change the solar temperature very near the center) • …

  20. Be neutrinos • - In the long run (Borexino+ KamLAND+LENS…) one can expect to measure FBe with an accuracy DFBe/FBe»5% • - FBe is insensitive to S17, however the uncertainty on S34will become important. • - FBe is less sensitive to the solar structure/temperature (FBe » T10). • An accuracy DFBe/FBe»5% will provide at best DT/T »0.5% • Remark however that Be and B bring information on (slightly) different regions of the Sun

  21. CNO neutrinos, LUNA and the solar interior • Solar model predictions for CNO neutrino fluxes are not precise because the CNO fusion reactions are not as well studied as the pp reactions. • Also, the Coulomb barrier is higher for the CNO reactions, implying a greater sensitivity to details of the solar model. • The principal error source is S1,14. The new measurement by LUNA is obviously welcome. • A measurement of the CNO neutrino fluxes would provide a stringent test of the theory of stellar evolution and unique information about the solar interior.

  22. Bahcall, Garcia & Pena-Garay Astro-ph 0212331 Does the Sun Shine by pp or CNO Fusion Reactions? • Solar neutrino experiments set an upper limit (3s) of 7.8% (7.3% including the recent KamLAND measurements) to the fraction of energy that the Sun produces via the CNO fusion cycle, • This is an order of magnitude improvement upon the previous limit. • New experiments are required to detect CNO neutrinos corresponding to the 1.5% of the solar luminosity that the standard solar model predicts is generated by the CNO cycle. • The important underlying questions are: • Is the Sun fully powered by nuclear reactions? • Are there additional energy losses, beyond photons and neutrinos?

  23. Summary • Solar neutrinos are becoming an important tool for studying the solar interior and fundamental physics • Better determinations of S17, S34 and S1,14 are needed for fully exploiting the physics potential of solar neutrinos. • All this brings towards fundamental questions: • Is the Sun fully powered by nuclear reactions? • Is the Sun emitting something else, beyond photons and neutrinos?

  24. Appendix

  25. Input and results of SSMs

  26. SSM (2000) • The model by Bahcall and Pinsonneault 2000 is generally in agreement with data to the “1sigma”level • Some possible disagreement just below the convective envelope (a feature common to almost every model and data set) YBP2000=0.244 YO= 0.249±0.003 RbBP2000-=0.714 RbO =0.711 ± 0.001 See Bahcall Pinsonneault and Basu astro-ph 0010346

  27. Calculated partial derivatives • Values of dlnY/ dlnX computed by using models including element diffusion. • For fluxes, values differing more than 10% from JNB values (in italics) are marked in red. There is excellent agreeement between our calculations and those of JNB.

  28. Be B Fi[109 /cm2/s] Fi[1010 /cm2/s] Fi[106 /cm2/s] pp N O Fi[108 /cm2/s] Fi[108 /cm2/s] pep T6 T6 Sensitivity to the central temperature* B -1000 solar models without diffusion, with cross sections and element abundances varied within their uncertainties * from Bahcall & Ulmer PRD 53, 4202 (1996)

  29. The measured S17(0) as a function of time From JNB astro-ph/0209080

  30. NACRE compilation adopted DB theory

  31. Junghans et al DB theory

  32. Hammache et al 2001 1998 DB theory

  33. Baby et al DB theory

  34. Strieder et al.

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