Presentazione di PowerPoint

1
Neutrino Geophysics Honolulu December 14-16,
2005
Fabio Mantovani Sienna University - Italy
Perspectives for geoneutrinos after KamLAND
results
based on work with L. Carmignani, G. Fiorentini,
T. Lasserre, M. Lissia, B. Ricci, S. Schoenert,
R. Vannucci
2
The Reference Model
Event yields from U and Th over the globe have
been calculated by using

• Observational data for Crust and Upper Mantle

• The BSE (Bulk Silicate Earth) Model constraint
  for Lower Mantle

• Th/U consistent with with chondritic prediction

• Best fit n-oscillation parameters

3
The Reference Model for KamLAND
We predict the produced antineutrino flux

• For Uranium

• For Thorium

F. Mantovani et al. Phys. Rev. D 69 2004 -
hep-ph/0309013
4
The origin of the flux at KamLAND
Contribute to the F Th in percentage
Contribute to the F U in percentage
Oceanic Crust
5
The region near KamLAND
We use a 2 x 2 degrees crust map, which
distinguishes several components (OC and CC,
sediments, upper, middle, lower)
6
Refining the Reference Model
KamLAND
We use

• A geochemical study of the Japan upper crust

• Detailed measurements of crust depth

• Selected values for Lower Crust

7
Refining the Reference Model
KamLAND
Regional uncertainties
G. Fiorentini et al. - Phys.Rev. D72 2005 -
hep-ph/0501111 / S. Enomoto PhD Thesis - 2005
8
How much Uranium is in the Earth? And where is it?
The contribution from the rest of the world
depends on the total mass of Uranium m as well as
on its distribution inside the Earth
9
The uncertainties of the Reference Model at
KamLAND

• uncertainty from the global Earth's structure
  and composition

• uncertainty of the regional contribution

10
Beyond the Reference ModelSignal and Heat at
KamLAND
G. Fiorentini et al. - Phys.Rev. D72 2005 -
hep-ph/0501111
11
In this scenario where are KamLAND results?
G. Fiorentini et al. - Phys.Lett. B 629 2005
- hep-ph/0508048
12
How to make the most of KamLAND signal
G. Fiorentini et al. - Phys.Lett. B629 2005 -
hep-ph/0508048 / S. Harissopulos et al. - 2005
13
Who is the enemy of geoneutrinos?
14
The goals of future experiments
15
The relation between signal TNU and heat TW
Sudbury
Homestake
Baksan
LENA
Borexino
KamLAND
Curacao (EARTH)
Hawaii
S (UTh) TNU
b depends on U and Th mass in the crust location
of the detector
Fully Radiogenic
BSE
H (UTh) TW
a is the universal slope
16
Measuring radioactivity from the crust
Based on the Reference Model constraints

• for each detector, almost 80 of the signal is
  expected from the crust

• these detectors will have excellent
  opportunities to determine the Uranium and
  Thorium abundance in the crust

• the uncertainties can be minimized studying the
  geochemical and geophysics properties of the
  region around the detector

• Homestake and Baksan have a better r factor
  (Ereactor/Egeo n)

17
Measuring radioactivity from the mantle
Based on the Reference Model constraints

• Borexino good for U and Th signal from the
  crust. It has a low r factor, but it has a small
  mass

• KamLAND it has a high r factor (Ereactor/Egeo
  n). It will be the first experiment which
  provide a definite evidence of geoneutrinos (3s)

• Curacao almost 25 of the signal is expected
  from the mantle and it has a low r factor
  (Ereactor/Egeo n)

• Hawaii almost 70 of the signal is expected
  from the mantle and it has a low r factor
  (Ereactor/Egeo n)

18
(No Transcript)
19
Can geoneutrinos measure the plumes depth?

• A mantle plume is an upwelling of anomalously
  hot rock in the Earth's mantle. Mantle plumes
  are thought to be the cause of volcanic centers
  known as hotspots Hawaii island is the most
  famous hotspot

Detector
hp

• We assumed cylindrical plume with uniform
  density and Uranium abundance ap(U)

rp
Computer simulation of a mantle plume by Hawaii
Scientific Drilling Project web site
With hpgtgtrp the geoneutrinos flux depends on the
asymptotic value Fas proportional to ap and rp
The U-neutrino flux from a plume with rp 350
km, hp 2800 km and ap(U) 40 ppb is about 20
of that from the whole mantle.
Fiorentini et all. - Earth and Planetary
Science Letters, Volume 238, 2005 -
physics/0508019
20
The lesson of solar neutrinos

• The study of solar neutrinos started as an
  investigation of the solar interior.

• Homestake experiment (Raymond Davis and
  colleagues) see the first solar neutrinos

• A long and fruitful detour lead to the
  discovery of oscillations.

• Through several steps, we have now a direct
  proof of the solar energy source, we are making
  solar neutrino spectroscopy, we have neutrino
  telescopes.

21
Follow this lesson!

• The study of geoneutrinos started as an
  investigation of the interior of the Earth
  Eder 1966 Marks 1969

• KamLAND experiment found the first evidence of
  geoneutrinos. The technique for identifying
  geo-neutrinos is now available.

• Whats the next?

22
geoneutrinos is a baby instrument that permit
us to look the Earth with new eyes
Let it grow!
23
Extra slides
24
Predictions of the Reference Model at KamLAND
25
The Reference Model
THE CRUST
AX depends on the life time, atom mass and number
of antineutrinos per decay chains
Average of
U 2,2 2,4 2,5 2,8
Th/U 3,8 3,8 3,9 4,1
Average of
U 0,2 0,28 0,93 1,1
Th/U 3,8 6,0 7,0 7,1
26
The Reference Model
THE MANTLE

• Assumptions
• Spherical symmetry
• Two reservoirs (geochemistrys model)
  discontinuity line at 600 km under the earth
  surface
• Uranium abundance in the Upper Mantle 6,5 ppb
  (the average of 5 8 ppb)
• The amount of Uranium mass in the Lower Mantle
  is obtained by the equation

MLM (U) MBSE (U) MCC (U) MOC (U) MUM
(U)
27
Predictions of the Reference Model at KamLAND
28
The uncertainties of the Reference Model at
KamLAND
The crust

• Using a 2 x 2 Crustal Model, for each of the
  six components we have fixed
• Thickness Km
• Density g/cm3
• Abundance of Uranium ppm

We obtained
The abundance ratios look relatively well
determined we concentrate on the uncertainties
of the uranium abundances in the different layers
and propagate them to the other elements.
(1) S. R. Taylor and S.M. McLennan 1985
(2) D. M. Shaw et al. 1986
29
A few words on directionality
30
Directionality at KamLAND
Vertical gt
lt Horizontal
31
Directionality at Hawaii
Vertical gt
lt Horizontal
Bin