View
213
Download
0
Tags:
Embed Size (px)
Citation preview
1
The pp-chain The pp-chain (and the CNO-cycle)(and the CNO-cycle)
after SNO and KamLAND after SNO and KamLAND
Barbara Ricci, University of Ferrara and INFN
Fourth International Conference on Physics Beyond the Standard Model“BEYOND THE DESERT ‘03”
Castle Ringberg, Tegernsee, Germany9-14 June 2003
2
3
OutlineOutline
• 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
4
The new era of neutrino physicsThe 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 Now that we know the fate of neutrinos, we can learn a lot a lot from from neutrinosneutrinos.
5
The measured The measured boron fluxboron flux
• The total active (e + + boron flux is now a measured quantity. By combining all observational data one has*:
= 5.05 (1 ± 0.06) 106 cm-2s-1.
• The central value is in perfect agreement with the Bahcall 2000 SSM
• Note the presentpresent 1 error is // =6% =6%
• In the next few yearsnext few years one hope to reach //3%3%
*Bahcall et al. astro-ph/0212147 and astro-ph/0305159
BP2000 FRANEC GARSOM
[106s-1cm-2]
5.05 5.20 5.30
1level
6
s33 s34
s17se7 s11
Nuclear
The Boron Flux, Nuclear The Boron Flux, Nuclear Physics and AstrophysicsPhysics and Astrophysics
astro• depends on nuclear physics
and astrophysics inputs
• Scaling laws have been found numerically and are physically understood
= (SSM) · s33
-0.43 s34 0.84 s17
1 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.
7
Uncertainties budgetUncertainties budget• Nuclear physics uncertainties,
particularly on S17 and S34 , dominate over the present observational accuracy
/ =6% (1.
• The foreseeable accuracy / =3% could illuminate about solar physics if a significant improvement on S17 and S34 is obtained.
• For fully exploiting the physics potential of a measurement with 3% accuracy one has to determine S17 and S34 at the level of 3% or better.
0.030.004Lum
0.030.10***Dif
0.050.02Opa
0.080.06Com
0.050.02S11
0.020.02Se7
+0.14
-0.07
+0.14
-0.07
S17**
0.080.09S34
0.030.06*S33
/S/S(1Source
*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 SProgress on S1717
S17(0)
[eV b]
Ref.
Adel.-Review. 19-2+4 RMP 70,1265 (1998)
Nacre-Review 21 ± 2 NP 656A, 3 (1999)
Hammache et al 18.8 ± 1.7 PRL 86, 3985 (2001)
Strieder et al 18.4 ± 1.6 NPA 696, 219 (2001)
Hass et al 20.3 ± 1.2 PLB 462, 237 (1999).
Junghans et al.* 22.3 ± 0.7 PRL 88, 041101 (2002)
Baby et al. 21.2 ± 0.7 PRL. 90,022501 (2003)
Results of direct capture expts**.
•Adelberger and NACRE use a conservative uncertainty (9%),
•Recently high accuracy determinations of S17 have appeared.
•Average from 5 recent determinations yields:
SS1717(0)= 21.1 (0)= 21.1 ±± 0.4 0.4 (1)
•In principle an accuracy of 2% has been reached, however dof=2 indicating some tension among different data.
S17
(0)[
eV b
]
Data published
**See also Davids & Typel (2003): 19 ± 0.5 eVb:
9
Remark on SRemark on S3434
• If really SS1717(0) (0) has a 2% accuracy, the 9% error of SS3434(0)(0) is the main source of uncertainty for extracting physics from Boron flux.
0.030.004Lum
0.030.10***Dif
0.050.02Opa
0.080.06Com
0.050.02S11
0.020.02Se7
0.020.020.020.02S17S17
0.080.080.090.09S34S34
0.030.06*S33
/S/S (1Source
• LUNA results on SLUNA results on S3434
will be extremely will be extremely important.important.
10
Sensitivity to the central temperatureSensitivity to the central temperature
• 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)
Bahcall and Ulmer. ‘96
i/
iSS
M
BB
BeBe
pppp
Tc/TcSSM
Castellani et al. ‘97
11
The central solar The central solar temperaturetemperature
• The various inputs to 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:
• = (SSM) [Tc /Tc(SSM) ]20. . S33
-0.43 S340.84 S17
Se7-1
SourcedlnT/dlnS
dlnB/dlnS
S33 0 -0.43
S34 0 0.84
S17 0 1
Se7 0 -1
S11 -0.14 -2.7 1919
Com +0.08 +1.4 1717
Opa +0.14 2.6 1919
Dif +0.016 0.34 2121
Lum 0.34 7.2 2121
•Boron neutrinos are excellent solar thermometers due to their high ((20)20) power dependence.
12
Present and future for measuring T with Present and future for measuring T with B-neutrinosB-neutrinos
• At present, // =6% =6% and SSnucnuc/ S/ Snucnuc= 12% (cons.)= 12% (cons.) translate into
Tc/Tc= 0.7 %Tc/Tc= 0.7 %
the main error being due to S17 and S34.
• If nuclear physics were perfect (SSnucnuc/S/Snuc nuc =0=0) already now we could have:
Tc/Tc= 0.3 %Tc/Tc= 0.3 %
• When // =3% =3% one can hope to reach (for Snuc/Snuc =0) :
Tc/Tc= 0.15 %1level
13
Helioseismic Helioseismic observables observables
From the measurements of p-modes one derives:
a)sound speed squared: u=P/(1) accuracy 0.1 – 1%, depending on the solar region
u/u1 3
See e.g. Dziembowski et al. Astr.Phys. 7 (1997) 77
b) properties of the convective envelope
Rb /Ro= 0.711(1± 0.14%) (1)
Yph=0.249 (1±1.4%)
u
14
SSM and SSM and helioseismologyhelioseismology• Standard solar models are
generally in agreement with data to the “(1) ” 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 Helioseismology constrains solar models and solar temperature (1)models and solar temperature (1)
•Temperature of the solar interior cannot be determined directly from helioseismology: chemical composition is needed: (u=P/T/ )
•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
S11 is constrained at 2% level (1) The metal content is constrained at the 5% level (1)
SS1111 Z/XZ/X
Examples:Examples:
•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
Helioseismology constrained solar Helioseismology constrained solar models and solar temperature (2)models and solar temperature (2)
BR et al. PLB 407 (1997) 155
•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: Helioseismic constraint: Tc/Tc= 0.5 %Tc/Tc= 0.5 %1level
18
Comparison between the two approachesComparison between the two approaches
•Helioseismic constrained solar models give:
Tc/Tc= 0.5 %Tc/Tc= 0.5 %
•Boron neutrinos observation translate into
Tc/Tc= 0.7 %Tc/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)
1level
19
The Sun as a laboratory The Sun as a laboratory for astrophysics and for astrophysics and fundamental physicsfundamental 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)
– …
BP-2000 FRANEC GAR-SOM
T6 15.696 15.69 15.7
20
Be neutrinosBe neutrinos
• In the long run (KamLAND +Borexino+LENS…) one can expect to measure Be with an accuracy Be/Be 5%
• Be is insensitive to S17, however the uncertainty on S34 will become important.
• Be is less sensitive to the solar structure/temperature (Be T10).
• An accuracy e/e 5% will provide at best
T/T 5%
SourceS/S (1
e/e
S33 0.06 0.03
S34 0.09 0.08
S17 +0.14
-0.07
=
Se7 0.02 =
Spp 0.02 0.02
Com 0.06 0.04
Opa 0.02 0.03
Dif 0.10 0.02
Lum 0.004 0.01
•Remark however that Be and B bring information on (slightly) different regions of the Sun
21
CNO neutrinos, LUNA CNO neutrinos, LUNA and the solar interiorand the solar interior
•The principal error source is S1,14. The new measurement by LUNA LUNA is obviously welcome.
SourceS/S (1)
/ O/O
S33 0.06 0.001 0.0008
S34 0.09 0.004 0.003
S17 +0.14
-0.07
0 0
Se7 0.02 0 0
Spp 0.02 0.05 0.06
S1,14 +0.11
-0.46
+0.09
-0.38
+0.11
-0.46
Com 0.06 0.12 0.13
Opa 0.02 0.04 0.04
Dif 0.10 0.03 0.03
Lum 0.004 0.02 0.03
•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.
22
SummarySummary• Solar neutrinosSolar 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 helioseismologyhelioseismology does
• 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 All this could bring us towards fundamental questions:questions:– Is the Sun fully powered by nuclear reactions?Is the Sun fully powered by nuclear reactions?– Is the Sun emitting something else, beyond photons Is the Sun emitting something else, beyond photons
and neutrinos?and neutrinos?
23
Appendix
24
pp-chainpp-chain99,77%
p + p d+ e+ + e
E 0,42 MeV
0,23%
p + e - + p d + e
E = 1,44 MeV
3He + 3He + 2p
S(0)=(5,4 0,4) MeVb
3He + p + e+ + e
E 18 MeV
~210-5 %84,7%
13,8%
0,02%13,78%
3He + 4He 7Be + S(0)=(0,52 0,02) KeV b
7Be + e- 7Li + + e
E 0,86 MeV
7Be + p 8B +
d + p 3He +
7Li + p +
pp I pp I pp IIIpp III pp IIpp II hephep
8B 8Be*+ e+ +e
2E 14,06 MeV
S(0)=(4,000,068)10-22 KeV b
25
Observations• On Earth: network of telescopes at different longitudines:
-Global Oscillation Network Group (GONG)-Birmingham Solar Oscillations Network (BiSON).
• From satellite:
since 1995: SoHo (Solar and Heliospheric Observatory)
GONG
D=1.5 10^6 km
26
Solar rotationSolar rotation• Solar surface does not rotate uniformely:
T=24 days (30 days) at equator (poles).
• 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 rotR2 0.02 eV Erot << KT
giornidays
http://bigcat.phys.au.dk/helio_outreach/english/
27
Magnetic fieldMagnetic 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 3
3
cm
erg
cm
erg
15
102
10nKT
104B
u
Radiative zone: B < 30MG, > 5 10-15 B
Tachocline B < 30000G, > 3 10-12 B
External zone, flux tube, B =4000G
28
• Calculate frequencies i as a function of u
ii(uj) j=radial coordinate
• Assume Standard Solar Model as linear deviation around the true sun:
ii, sun + Aij(uj-uj,sun)• Minimize the difference between the measured i
and the calculated i
• In this way determine uj=uj-uj, sun
Inversion methodInversion method
2
i i
ii2
29
Does the Sun Does the Sun Shine by pp or Shine by pp or CNO Fusion CNO Fusion Reactions?Reactions?
• Solar neutrino experiments set an upper limit (3) 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.
Bahcall, Garcia & Pena-Garay PRL 2003