Model independent extraction of the axial mass parameter from antineutrino-nucleon. scattering data. By: Jerold Young Adviser: Dr.

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1 Model independent extraction of the axial mass parameter from antineutrino-nucleon CCQE scattering data By: Jerold Young Adviser: Dr. Gil Paz

2 The Neutrino Created as a result of certain types of radioactive decay (β Decay), or nuclear reactions Electrically Neutral Weakly interacting elementary subatomic particle Half-integer spin 2

3 Flavors of Neutrinos 3

4 Neutrino Oscillations Quantum mechanical phenomenon Neutrino created with a specific lepton flavor (electron, muon or tau) can later be measured to have a different flavor. Probability of measuring a particular flavor for a neutrino varies periodically as it propagates Observation of the phenomenon implies that the neutrino has a non-zero mass Not part of the original Standard Model of particle physics. 4

5 MiniBooNE 5

6 Axial Mass Least Constrained form factor, F A (q 2 ) q 2 is taken to be the transfer momentum four vector where Q 2 = q 2. 6

7 Axial Mass World Averages As is evident by the values on the left there is a distinct discrepancy between values of Axial Mass. A method that produces consentient measurements is needed! World average value: M A dipole = ± GeV V. Bernard et al., J. Phys. G28, R1 (2002). Nomad: M A dipole = 1.05 ± 0.02 ± 0.06 GeV NOMAD Collaboration, EPJ C 63, 335 (2009) K2K SciFi: M A dipole = 1.20 ± 0.12 GeV K2K Collaboration, PRD (2006) MiniBooNE: M A dipole = 1.35 ± 0.17 GeV MiniBooNE Collaboration, PRD (2010) 7

8 Discrepancy's in Data Analysis of Neutrino Scattering Events As seen in the graph a value of M A =1.35 GeV is needed to fit the data which is in contradiction to the world average 8 MiniBooNE Collaboration PRD 81 (2010)

9 Model Dependent Method for Data Analysis The value of F A (0) is This method is a one parameter model which assumes that M Dipole A = M A. This method overly constrains parameters 9

10 Model Independent Method for Data Analysis z expansion When using a model dependent analysis to extract values for axial mass we see inconsistent values. However when using a model independent method such as the z expansion we obtain much more consistent values between the different experiments Value obtained using z expansion m A = GeV Taking into account the error bars we can see that this value is much more consistent with the world average, ± GeV 10 [B. Bhattacharya, R. J. Hill, and G. Paz, Phys. Rev. D 84, (2011).]

11 Neutrino and anti-neutrino scattering Events Neutrino: ν μ + n μ + p Anti-neutrino:ν μ + p μ + + n Scattering targets (n vs. p) C n H 2n+2 Scattering ( where n 20) targets material (n vs. p) Neutrons in Carbon only CH 2 target material neutrons Protons in both Carbon and Hydrogen 11 in carbon only Protons in both carbon and hydrogen

12 Results of μmm R ΡR J Τ 12

13 Goals Run C12 data using current code. Examine results and modify code in order to account for scattering from hydrogen in mineral oil Develop a statistical model to implement the free proton from hydrogen into the code. Extract m A using both dipole method and z-expansion for mineral oil 13

14 C12 Antineutrino Scattering Data Previous Analysis by former REU student has shown results of anti-neutrino C 12 m A data (m A = where Q2 max =1.00GeV 2 ) to be in agreement with neutrino results obtained by Dr. Paz and collaborators. However over the past year the data reported by MiniBooNE was changed. Thus a Reevaluation was needed. 14

15 Comparison of past and current Antineutrino C12 data analysis Summer 2013 Summer m A = Gev m A = Gev Antineutrino 15

16 Mineral Oil Analysis One of the main goals of this summers research was to obtain a statistical model that would allow for the combination of Hydrogen and Carbon s Cross Sections in order to obtain a Cross Section for Mineral Oil. 16

17 Mineral Oil Analysis The Mineral oil has a chemical formula of C n H 2n+2 ( where n 20) The Statistical model developed uses this information to produce the following formula dσ = 20σ C+42σ H (for Mineral Oil) 62 Where σ is the cross section Factors of 20,42 and 62 were obtained from number of atoms in mineral oil molecule 17

18 Mineral Oil Analysis At this Current time implementation of this model into the code has not been achieved. 18

19 Neutrino Energy Analysis First step in implementing the Statistical model is to be able to reconstruct the incident neutrino energy. This was achieved by deriving a formula for E ν in terms of scattering angle θ and the kinetic energy of the lepton T E ν = m l 2 2(T + m l )m n 2( T + m l m n T + m l 2 m l 2 cos(θ) 19

20 Conclusions When running the C12 analysis with the new data release we see that there is an agreement with previous results however there is a anomalous reading at 0.1 GeV Determined m A for C12 to be Gev which is in good agreement with value obtained by Dr. Paz and collaborators of m A = GeV Developed statistical model to implement proton from Hydrogen into the code. 20

21 Future Work Determine why 0.1 GeV 2 gives anomalous reading for C12 data Fully Integrate Statistical model into code Extract Axial Mass parameter for Mineral Oil Compare obtained value with values obtained in other analysis 21

22 Acknowledgements I would like to thank the Wayne State University department of Physics for giving me this opportunity I would like to express my sincerest gratitude to Dr. Paz for his guidance and help. 22