Transcript Status of neutrino mass-mixing parameters and implications

Venice, April 15, 2008
What we (would like to) know about the
neutrino mass
Gianluigi Fogli
QuickTime™ e un
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Gianluigi Fogli
Dipartimento di Fisica dell’Università di Bari & Sezione INFN - Bari
Based on work done in collaboration with:
E. Lisi, A. Marrone, A. Melchiorri, A. Palazzo, P. Serra, J. Silk, A. Slosar
NO-VE
2008, IV International
Workshop on “Neutrino Oscillations in Venice”1
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
Outline
1.
Updating neutrino oscillation parameters
2.
Updating non-oscillation observables
3.
Interplay of oscillation/non-oscillation bounds
4.
Constraining (some) 02 theoretical uncertainties
5.
Conclusions
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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1. Updating neutrino oscillation parameters
Based on:
GLF, Lisi, Marrone, Melchiorri, Palazzo, Serra, Silk, Slosar
Addendum to arXiv:hep-ph/0608060 (in preparation)
GLF, Lisi, Palazzo, Rotunno
Geo- analysis (in preparation)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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MINOS 2007 (preliminary) and KamLAND 2008 data provide a better
determination of the two independent neutrino oscillation frequencies:
oscillations driven by
m2 ~ 2.4 x 10-3 eV2
oscillations driven by
m2 ~ 7.6 x 10-5 eV2
(Recent solar neutrino results from Borexino 2007 and SK-phase II 2008
do not affect yet the global analysis of neutrino mass/mixing parameters)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Visible progress from 2006 (dashed) to 2008 (solid)
“Solar” neutrinos
Gianluigi Fogli
“Atmospheric” neutrinos
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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2008 parameter summary at 2 level (95 % CL)
(Addendum to hep-ph/0608060, in preparation)
This is what we know.
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Concerning
What we would like to know
Hierarchy (normal or inverted)
CP in the  sector
13 mixing
Some aspect is currently “hidden” below 1 C.L.
A recent example:
slight preference for
sin213 ~ 0.01
from the combination of
solar+reactor 2008 data
(green curve in the figure)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Reason:
Slight disagreement between
• Solar data (SNO dominated)
• KamLAND data (at 13 = 0)
when the two best-fits are compared
in the usual plane (m212, tan212)
[figure taken from the official Kamland site (2008)]
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Disagreement reduced for 13 > 0 …
sin213 = 0
sin213 = 0.03
(figures prepared by A.M. Rotunno for this talk)
… thanks to the different dependence in SNO and KamLAND from (13 , 12).
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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A tiny effect, of course,
but with some potential for improvement, once final SNO data and further
KamLAND data will be available.
Let’s now switch to the
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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2. Updating non-oscillation observables
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Three absolute mass observables: m, m, 
that depend on the parameters measured in  oscillations:
1)
 decay
a very good approximation, valid if energy smearing prevents
observation of separate “Kurie plot kinks”
2)
02 decay
expression basically exact (as far as no RH currents or new
physics interfere with light neutrino exchange)
3)
Cosmology
leading sensitivity related to the sum of the masses; in the (far)
future, maybe some weak sensitivity to mass spectrum hierarchy
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Some updates in the last 1-2 years
1)
 decay:
None (waiting for KATRIN)
2)
02 decay:
Final results from Klapdor et al. (2006);
Revised nuclear matrix elements and uncertainties (2007);
Cuoricino results (2008)
3)
Cosmology:
WMAP 5 year data (2008)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Cosmology (one year ago)
Limits depend on the input data sets:
Power Spectrum of density fluctuations
• CMB (WMAP3y + others)
• Sloan Digital Sky Survey (SDSS)
• Type Ia Supernovae (SN)
• Big Bang Nucleosynthesis (BBN)
• Large Scale Structure (LSS)
• Hubble Space Telescope (HST)
in terms of
fν =
ν
m
• Baryon Acoustic Oscillations (BAO)
• Lyman-(Ly-)
Bounds on
Gianluigi Fogli
 for increasingly rich data sets (assuming flat CDM model):
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Constraints on  from Cosmology (one year ago)
Constraints from Cosmology
Case 7: most “aggressive” (all
available cosmological data)
Upper limits range from ~2 to
~0.2 eV at 95% C.L., but no
consensus on a specific value yet
Gianluigi Fogli
standard deviations
Case 1: most “conservative” (only
1 data set: WMAP 3y)
 (eV)
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Cosmology today
Unfortunately the global analysis is not ready: work is in progress.
We can only present the preliminary
results coming from CMB data alone
after WMAP 5y
 < 1.3 eV at 2
Of course, we expect the limit
strengthened in the sub-eV range by
LSS + other data
preliminary
[Always adopting the usual caveats about
the CDM model, its matter-energy
content, and the way in which the other
data sets are included.]
Gianluigi Fogli
(Addendum to arXiv:hep-ph/0608060, in preparation)
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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02 decay update
A true dilemma …
evidence …
Quic kTime™ and a
TIFF ( Unc ompres s ed) dec ompr es sor
are needed to s ee this pic tur e.
or
Klapdor et al.: MPLA 21, 1547 (2006)
no evidence?
Cuoricino, arXiv:0802.3439 [hep-ex]
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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02 decay - evidence
• Claim of 02 decay in 76Ge controversial, but:
• Sensitivity to signal, in principle, is no longer disputed.
• Final results by Klapdor et al.: MPLA 21, 1547 (2006).
In combination with recent nuclear matrix elements and uncertainties
from Simkovic et al., arXiv:0710.2055 [nucl-th], these results would
provide the 2 preferred range:
lower and more conservative than it was adopted ~2 years ago
(Addendum to arXiv:hep-ph/0608060, in preparation)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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02 decay - no evidence
• Cuoricino has found no 02 decay signal in 130Te.
• Recent results in arXiv:0802.3439 [hep-ex].
• Half life in 1024 years: T > 3.1 (90% CL); T > 2.5 (95% CL)
In combination with recent nuclear matrix elements and uncertainties
from Simkovic et al., arXiv:0710.2055 [nucl-th], these results would
provide the 2 upper limits:
where the spread (…) is due to theoretical uncertainties.
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Comparing
• the preferred 2 range by Klapdor et al.
• the 2 upper limits by Cuoricino
m [0.16, 0.52] eV
m [0.23, 0.85] eV
we see that Cuoricino is starting to probe the 76Ge 02 claim, but current theory
errors (in different isotopes) prevent definite statements.
So, concerning
What we would like to know
the Dirac or Majorana
nature of neutrinos
It is still hidden in the data, with further uncertainties arising from the theory
of nuclear structure. [More about the attempt of error reduction later].
Let’s now switch to the
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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3. Interplay of oscillation/non-oscillation bounds
Based on:
GLF, Lisi, Marrone, Melchiorri, Palazzo, Serra, Silk, Slosar
Addendum to arXiv:hep-ph/0608060 (in preparation)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Interplay/1
Oscillations fix the mass2 splittings, and thus induce positive correlations
between any pair of the three observables (m, m, ), e.g.:
m

i.e., if one observable increases, the other one (typically) must increase to
match the mass2 splitting.
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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In the absence of new physics (beyond 3 masses and mixing),
determinations of any two observables among (m, m, ) are expected
to cross the oscillation band
Interplay/2
m

This requirement provides either an important consistency check or, if not
realized, an indication for new physics (barring expt. mistakes)
 Analysis of established oscillation data is an important ingredient
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Bands from 2008 osc. data for normal and inverted hierarchy
Inverted
Degenerate (overlap)
Bands overlap when mass
splittings are small with respect
to the absolute masses:
Normal
Majorana
phase(s)
spread
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Intermezzo: Dreaming about future precise data below 0.1 eV…
e.g., if…
Data = green “dot” in the
figure, then …
in principle, one might, with
some luck:
Check the overall consistency
between oscill./nonoscill. data …
Identify the hierarchy …
(inverted, in this case)
Probe the Majorana phase(s) …
(i.e., reduce vertical spread in m)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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… back to real
life
Relevant example including previous 2008
updates:
Constraints from
oscillations + WMAP 5y + 02 claim
They admit a global combination at 2
(thick black wedge in the figure)
But no combination if

< 0.45 eV
from cosmology (WMAP + other data)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Assuming the previous combination
Each (degenerate) neutrino mass should be found in the 2 range:
m1  m2  m3  0.15 - 0.80 eV
This range is largely accessible to the KATRIN expt. (except below ~0.2 eV).
Possible outcomes within the reach of Katrin might be, e.g., (1 errors):
m =
0  0.12 (< 0.2 at 90% CL)
m = 0.30  0.10 (3 evidence)
KATRIN
discovery potential
m = 0.35  0.07 (5 discovery)
Let’s now switch to the
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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4. Constraining (some) 02 theoretical uncertainties
Based on:
Faessler, GLF, Lisi, Rodin, Rotunno, Simkovic
arXiv:0711.3996 [nucl-th]
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Benchmarking Nuclear Matrix Elements (NME)
In principle, any nuclear model used to calculate the 02 NME for a given
nucleus, should also be able to describe all the other (allowed) weak-interaction
processes for that nucleus:
22 decay,  decay, EC, C,
and
charge-exchange reaction.
The available weak-interactions data could then be used to benchmark the nuclear
model parameter space and reduce NME uncertainties.
For example, QRPA* calculations involve a particle-particle interaction strength
gpp ~ O(1)
In principle, a single datum can be used to fix gpp (value  error).
*Quasiparticle Random Phase Approximation
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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A lot of measurements available: our Compilation
BUT: Data of different quality and not always in agreement with each other.
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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We restrict ourselves
To safest data set: lifetimes of
to the only three nuclei for
which all these data are available
22 decay
 decay
EC
100Mo
116Cd
128Te
Note: Unfortunately this choice excludes, at the moment,
in the two experiments discussed before.
Gianluigi Fogli
76Ge
and 130Te, used
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Two conflicting approaches so far
Rodin, Faessler, Simkovic &
Vogel:
use 22 decay data to fix
gpp
Civitarese & Suhonen:
use  decay (or EC) to fix
gpp
Debate between the two groups about which approach is better
Both approaches, however,
face a severe problem:
Difficult to fit both 22 and  decay
(EC) data within the same gpp range
[In any case, such experimental constraints cannot reduce those
theoretical systematics which are peculiar of 02 decay, such
as the so-called “short-range correlation” (SRC) effects]
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Our approach: Strong Quenching
We suggest that this discrepancy may be related to unnecessarily restrictive
choices for the effective axial coupling (gA) in nuclear matter.
Experimentally, the observed Gamow-Teller strength (~ gA2) in nuclei is
weaker than in vacuum:
gA < 1.25
“quenching”
Usually, quenching is implemented by taking
gA ≈ 1
“standard quenching”
BUT: Amount and origin of quenching in different nuclei is still debated. Usual
practice (gA ≈ 1) should not be considered as a “dogma”, and data-driven
departures may well be possible. In our case:
gA = 0.84
Gianluigi Fogli
“strong quenching”
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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E.g., 116Cd with gA = 1
22
“standard” quenching
QRPA estimates 1
EXPT data 1
Preferred gpp range
EC
Disjoint gpp ranges
[Twofold ambiguity for 22 and -]
-
Problem worse for gA = 1.25 (“bare”)
Q.: Can gA<1 help? Yes.
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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E.g., 116Cd with gA = 0.84
22
“stronger” quenching
QRPA estimates 1
EXPT data 1
Preferred gpp range
EC
Common gpp range, 0.4-0.6
[Ambiguity solved]
-
gA = 0.84 not much lower than gA = 1
If we accept gA < 1, then …
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Search for the regions allowed in the plane (gpp, gA)
116Cd
100Mo
128Te
The panels show, for each nucleus, the 1 bands for the three processes
(22, EC and  –) and the corresponding best fit
This provides a possible way to reduce the uncertainties in the parameters
(gpp, gA), which also affect the 02 NME (Nuclear Matrix Elements)
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Implications for the 02 Nuclear Matrix Elements
We compare
…
Our results (theory in agreement
with 22, -, and EC data)
Previous results (gA=1 fixed,
theory in agreement only with
22 data)
Apparently not very different,
but big gain in understanding and
controlling errors.
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Some further remarks on 02 NME
The unconventional hypothesis gA < 1 must certainly pass further tests.
Anyway, we hope that our approach may spark new interest towards a larger
research program to benchmark the 02 nuclear models in more nuclei and
with more data.
This is mandatory to reduce 02 theoretical uncertainties and make the
best use of experimental results in terms of m.
Let’s now switch to the
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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5. Conclusions
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Going back to the title …
We know …
… already a lot about neutrinos, mainly because of the extremely rapid progress
in oscillation searches during the last decade 1998-2008 …
but …
… concerning what
We would like to know …
… we need to be patient, in particular to access absolute neutrino masses…
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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“Moore’s law” : factor of ~10 improvement every ~15 years
2000
KATRIN,
MARE ?
2015
?
2000
CUORICINO,
GERDA …
2015
2030
WMAP
?
2015
Gianluigi Fogli
2000
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
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Indeed, an impressive lot of time …
… but, on a much shorter timescale, let me invite all of you at
NOW 2008, Conca Specchiulla, Sept. 6-13 (www.ba.infn.it/~now2008)
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
QuickTime™ and a
TIFF (Uncompressed) decompressor
are needed to see this picture.
See you there!
Gianluigi Fogli
IV International Workshop on “Neutrino Oscillations in Venice”, Venice, April 15, 2008
42