How to Measure the Charge of Neutrinos

Transcription

1 How to Measure the Charge of Neutrinos Group 11 Lingjun Fu Michelle Mesquita de Medeiros Richa Sharma

2 LIGHT AT THE END OF THE TUNNEL

3 IT S THE SUN!

4 CONES Charge Of Neutrino Experiment/Search

5 Introduction Neutrinos are believed to have a zero electric charge - conservation of charge in beta decay But in a large class of gauge models, including the Minimal Supersymmetric Standard Model, electric charge can be dequantized This means that the neutrino can acquire a non-zero electric charge All which is not forbidden is allowed The question is: What would be the consequences of this charge, and how can we detect it? 5/20

6 Existing Constraints Analysis of data on (νe e) elastic scattering: q < 3x10-10 e Study of em neutrino interaction in the Sun: q < e SN1987A supernova explosion: q < e Experimental data on the neutrality of the atom and neutrality of the protons: q < (-0.4+/-1.1) x e 6/20

7 How to measure the neutrino charge? Consider electron neutrinos coming from the Sun Deflection in the magnetic field: 1.Interplanetary Magnetic Field 2.Geomagnetic Field Measure the deflection using detector on Earth L =... km L =... km 7/20

8 What do we want to observe? Sun L = 4.849x10-6 kpc B = 6 µg (Average) θ Measure the deflection θ L = 3.09x10-9 kpc B = 0.6 G (Average) 8/20

9 Neutrino Interactions Two kinds of interactions: Elastic Scattering Better measurement of neutrino direction Charged Current Better measurement of neutrino energy 9/20

10 Characteristics of the Detector Underground detector, to reduce background Situated at north or south pole (Antarctica?) - experience maximum B field Require very good angular resolution - to measure the small deflection Good energy resolution - large PMT coverage 10/20

11 Detector Consist of two kinds of targets: - Water target (Elastic Scattering) - Chlorine target (Charged Current) PMT coverage Water Chlorine PMTs 11/20

12 Acceptance Global Acceptance - - avoid matter effects Local Acceptance - - only look at the neutrinos from the Sun -85 to +85 degrees 0.7 degrees Detector Earth 12/20

13 Expected deflection Interplanetary Magnetic Field: S = x 10-6 kpc B = 6 µg (Average) E = 20 ev (Average) for Z = 3 x 10-21, δ = x degrees 13/20

14 Expected deflection Geomagnetic Field S = 3.09 x 10-9 kpc B = µg (Average) E = 20 ev (Average) for Z = 3 x 10-21, δ = x degrees 14/20

15 Expected deflection - Total For Z = 3x10-21, Total deflection δ = x degrees Deflection vs Charge Deflection (degrees) Charge x10-17 e x10-16 e x10-16 e Will be able to measure it 15/20

16 How to measure it We want an angular resolution better than 0.1 degrees Cannot count event by event - measure the phase space Use statistical tests - log-likelihood techniques x Expectation with a small electric charge Expectation with no electric charge 16/20

17 Why not make a neutrino beam on earth? Solar neutrinos are free! IMF and geomagnetic field, though small, can cause an observable deflection because of the large distance travelled Equivalent deflection using a large B field on earth with a small L. δ B.L Can also be adapted to use other stars as source 17/20

18 More Physics! Dirac vs Majorana? - Neutrinos and antineutrinos should have opposite electric charge Measure antineutrino flux - Solar antineutrinos, or - Could come from neutrino to antineutrino oscillations Detect neutrinos through their electromagnetic interaction Better ways of managing neutrino beams, creation of neutrino optics etc If neutrinos have charge they can carry information like electromagnetic waves - Communication 18/20

19 Conclusion Neutrinos can have a small electric charge We can measure it using solar neutrinos from their deflection in the magnetic field Requires very high sensitivity to direction It would allow us to study the neutrino properties in a lot of new ways 19/20

20 THANK YOU! 20/20