1 / 29

The pp-chain (and the CNO-cycle) after SNO and KamLAND

The pp-chain (and the CNO-cycle) after SNO and KamLAND. Fourth International Conference on Physics Beyond the Standard Model “BEYOND THE DESERT ‘03” Castle Ringberg, Tegernsee, Germany 9-14 June 2003. Barbara Ricci, University of Ferrara and INFN. FAPG. Ferrara AstroParticles Group

meagan
Download Presentation

The pp-chain (and the CNO-cycle) after SNO and KamLAND

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. The pp-chain (and the CNO-cycle) after SNO and KamLAND Fourth International Conference on Physics Beyond the Standard Model “BEYOND THE DESERT ‘03” Castle Ringberg, Tegernsee, Germany 9-14 June 2003 Barbara Ricci, University of Ferrara and INFN

  2. FAPG Ferrara AstroParticles Group (University and INFN)

  3. Outline • Boron-neutrinos after SNO and KamLAND • What can we learn from B-neutrinos? • What have we learnt from Helioseismology? • The Sun as a laboratory for fundamental physics • Main messages: • Neutrinos are now probes of the solar interior • accurate determinations of S17,S34 and S1,14 are particularly important now.

  4. DM SN Earth The new era of neutrino physics • 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. Sun

  5. 1s level 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 hope to reach DFB/FB»3% *Bahcall et al. astro-ph/0212147 and astro-ph/0305159

  6. FB The Boron Flux, Nuclear Physics and Astrophysics s33s34s17se7s11 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 s11-2.7 · 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.

  7. Source DS/S(1s) DFB/FB Uncertainties budget S33 0.06* 0.03 S34 0.09 0.08 S17** +0.14 -0.07 +0.14 -0.07 • Nuclear physics uncertainties, particularly on S17 and S34 , dominate over the present observational accuracy DFB/FB =6% (1s ). • 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. Se7 0.02 0.02 S11 0.02 0.05 Com 0.06 0.08 Opa 0.02 0.05 Dif 0.10*** 0.03 Lum 0.004 0.03 • *LUNA result • **Adelberger Compilation: see below • ***by helioseismic const. • [gf et al.A&A 342 (1999) 492] • See similar table in JNB, astro-ph/0209080

  8. Progress on S17 S17(0)[eV b] • Adelberger and NACRE use a conservative uncertainty (»9%), • Recently high accuracy determinations of S17 have appeared. • Average from 5 recent determinations yields: • S17(0)= 21.1 ± 0.4 (1s) • In principle an accuracy of 2% has been reached, however c2/dof=2 indicating some tension among different data. Data published Results of direct capture expts**. **See also Davids & Typel (2003): 19 ± 0.5 eVb :

  9. Source DS/S (1s) DFB/FB Remark on S34 S33 0.06* 0.03 S34 0.09 0.08 S17 0.02 0.02 • If really S17(0) has a 2% accuracy, the 9% error of S34(0) is the main source of uncertainty for extracting physics from Boron flux. Se7 0.02 0.02 S11 0.02 0.05 Com 0.06 0.08 Opa 0.02 0.05 Dif 0.10*** 0.03 Lum 0.004 0.03 • LUNA results on S34 will be extremely important.

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

  11. 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 pp-chain branches without changing solar structure. • The effect of the others can be reabsorbed into a variation of the “central” solar temperature: • FB =FB(SSM) [Tc /Tc(SSM) ]20. .S33-0.43 S340.84 S17 Se7-1 • Boron neutrinos are excellent solar thermometers due to their high (»20) power dependence.

  12. 1s level Present and future for measuring T with B-neutrinos • At present, DFB/FB =6% and DSnuc/ Snuc= 12% (cons.) translate into DTc/Tc= 0.7 % the main error being due to S17 and S34. • If nuclear physics were perfect (DSnuc/Snuc =0) already now we could have: DTc/Tc= 0.3 % • When DFB/FB =3% one can hope to reach (for DSnuc/Snuc =0) : DTc/Tc= 0.15 %

  13. Du/u 1s3s u Helioseismic observables From the measurements of p-modes one derives: a)sound speed squared: u=P/r (1s) accuracy » 0.1 – 1%, depending on the solar region b) properties of the convective envelope Rb /Ro= 0.711(1± 0.14%) (1s) Yph=0.249 (1±1.4%) See e.g. Dziembowski et al. Astr.Phys. 7 (1997) 77

  14. SSM and helioseismology • Standard solar models are generally in agreement with data to the “(1s)” level: e.g. BP2000 • Some possible disagreement just below the convective envelope (a feature common to almost every model and data set) YBP2000=0.244 Y= 0.249±0.003 RbBP2000=0.714 Rb=0.711 ± 0.001 BP2000=Bahcall et al. ApJ 555 (2001) 990

  15. Helioseismology constrains solar models and solar temperature (1) • Temperature of the solar interior cannot be determined directly from helioseismology: chemical composition is needed: (u=P/r »T/ m) • But we can obtain the range of allowed values of Tc by using th following approach: • build solar models by varying the solar inputs which mainly affect Tc (S11, chemical composition, opacity…) • select those models consistent with helioseismic data(sound speed profile, properties of the convective envelope)

  16. Examples: Z/X S11 The metal content is constrained at the 5% level (1s) S11 is constrained at 2% level (1s) • Actually one has to consider: • 1) all parameters which affect Tc in the proper way (compensation effects) • 2) not only sound speed, but above all the properties of the convective envelope .…..

  17. 1s level Helioseismology constrained solar models and solar temperature (2) • Temperature of the solar interior cannot be determined directly from helioseismology • So - if we build solar models by varying the solar inputs which mainly affect Tc • -and select those models consistent with helioseismic data(sound speed profile, properties of the convective envelope) • We find: Helioseismic constraint: DTc/Tc= 0.5 % BR et al. PLB 407 (1997) 155

  18. 1s level Comparison between the two approaches • Helioseismic constrained solar models give: • DTc/Tc= 0.5 % • Boron neutrinos observation translate into • DTc/Tc= 0.7 % • (main error being due to S17 and S34) • For the innermost part of the sun, neutrinos are now almost as accurate as helioseismology • (They can become more accurate than helioseismology in the near future)

  19. The Sun as a laboratory for astrophysics and fundamental physics • An accurate measurement of the solar temperature near the center 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 emission) • Dark matter (if trapped in the Sun it could change the solar temperature very near the center) • …

  20. Be neutrinos • In the long run (KamLAND +Borexino+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.

  22. Summary • Solar neutrinos are becoming an important tool for studying the solar interior and fundamental physics • At present they give information about solar temperature as accurate as helioseismologydoes • Better determinations of S17, S34 and S1,14 are needed for fully exploiting the physics potential of solar neutrinos. • All this could bring us towards fundamental questions: • Is the Sun fully powered by nuclear reactions? • Is the Sun emitting something else, beyond photons and neutrinos?

  23. Appendix

  24. 8B 8Be*+ e+ +e 2 E 14,06 MeV pp-chain 99,77% p + p  d+ e+ + e E 0,42 MeV 0,23% p + e - + p d + e E= 1,44 MeV S(0)=(4,000,068)10-22KeVb 84,7% ~210-5 % d + p 3He + 13,8% 3He + 4He7Be +  S(0)=(0,52  0,02) KeV b 13,78% 0,02% 7Be + e-7Li +  + e E 0,86 MeV 7Be + p 8B +  3He + 3He  + 2p S(0)=(5,4  0,4) MeVb 7Li + p  +  3He + p + e+ + e E 18 MeV pp I pp II pp III hep

  25. Observations • On Earth: network of telescopes at different longitudines: -Global Oscillation Network Group (GONG) -Birmingham Solar Oscillations Network (BiSON). GONG • From satellite: • since 1995: SoHo (Solar and Heliospheric Observatory) D=1.5 10^6 km

  26. giorni Solar rotation • Solar surface does not rotateuniformely: T=24 days (30 days) at equator (poles). days • Helioseismology (after 6 years of data taking) shows that below the convective region the sun rotates in a uniform way • Note: Erot =1/2 m wrotR2» 0.02 eV Erot << KT http://bigcat.phys.au.dk/helio_outreach/english/

  27. Radiative zone: B < 30MG, mn > 5 10-15mB Tachocline B < 30000G, mn > 3 10-12mB External zone, flux tube, B =4000G Magnetic field • From the observation of sunspots number a 11 year solar cycle has been determined (Sunspots= very intense magnetic lines of force (3kG) break through the Sun's surface) • the different rotation between convection and radiative regions could generate a dynamo mechanism: • B< 30 kG near the bottom of the convective zone.( e.g. Nghiem, Garcia, Turck-Chièze, Jimenez-Reyes, 2003) • B< 30 MG in the radiative zone • Anyhow also a 106G field give an energy contribution << KT

  28. Inversion method • Calculate frequencies wi as a function of u wi = wi(uj) j=radial coordinate • Assume Standard Solar Model as linear deviation around the true sun: wi=wi, sun + Aij(uj-uj,sun) • Minimize the difference between the measured Wi and the calculated wi • In this way determine Duj=uj-uj, sun

  29. Does the Sun Shine by pp or CNO Fusion Reactions? Bahcall, Garcia & Pena-Garay PRL 2003 • 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.

More Related