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.

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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

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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:

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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.

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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

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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.

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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

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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

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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

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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)

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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 .…..

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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

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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

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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

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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

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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.

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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?

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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

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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

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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/

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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

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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