oscillations with a polarized laser beam: an analogical demonstration experiment

Size: px

Start display at page:

Download "oscillations with a polarized laser beam: an analogical demonstration experiment"

Ginger Fields
6 years ago
Views:

1 oscillations with a polarized laser beam: an analogical demonstration experiment Int. School on Nuclear Physics, Erice, Italy, September 16-24, 2009 C. Weinheimer, H. Baumeister, T. Bode, P. Boschan, G. Hackmann Westfälische Wilhelms-Universität Münster, Germany weinheimer@uni-muenster.de Motivation 2 flavour vacuum oscillation Bifringence Optical analogue Experiment 1

2 Motivation: neutrino oscillation is one of the largest discoveries of the last decade in nuclear/particle/astroparticle physics our only evidence for physics beyond the Standard Model so well proven, that it turned into textbook knowledge based on a general feature of mixed two-state systems, e.g. K0 K0 (B0 B0,..) oscillation does not need advanced quantum physics, but is not easy to understand for senior high school or 1st/2nd year university students although they are familiar with the double slit experiment Try to explain neutrino oscillation without simplifications by an analogue experiment using the two state system of polarized light, which can be permformed in senior high school classes / with 2nd year students 2

3 Neutrino (vacuum) oscillations Incredients: 1) non-trivial mixing matrix U between neutrino flavour states ( e ) and mass states ( 1, 2, ): 2) a flavour state propagates as a coherent sum of mass states m( i) if the m( i) differ neutrino oscillation 1 U * W+ l + U 1 2 * W+ U U 2 l 3 U 3 U * detection of a creation of a propagation as coherent via weak interaction superposition of mass states via weak interaction P( ) 3

4 2 flavour neutrino (vacuum) oscillations: the two essential incredients ing s mix e t a t s 2 W+ - sin cos 1 2 e+ cos -sin e W+ ent m i r e p slit ex e l b u Do pure flavor rotating back propagation rotating pure flavour 4

$..) it exhibits different refraction indices A birefringent crystal has one optical axis ordinary beam: pol.$ $vector E to optical axis with refraction index no picture: A. Peter picture: wikipedia extraordinary beam: pol.$

5 Reminder: birefringence If an optical medium is anisotropic (intrinsic, by a tension,...) it exhibits different refraction indices A birefringent crystal has one optical axis ordinary beam: pol. vector E to optical axis with refraction index no picture: A. Peter picture: wikipedia extraordinary beam: pol. vector E (partly) to optical axis with refraction index ne 0 optical axis 001 picture: wikipedia No double image but different phase propagation, if the entrance surface of the crystal contains the optical axis calcite 5

6 2 polarized photon state oscillations: the same two incredients ing s mix e t a t s 2 W+ - sin cos o e e+ cos -sin e W+ ent m i r e p slit ex e l b u Do pure flavor rotating back propagation rotating pure flavour complete equivalence of formalism for m2 n E /4 6

7 Idea of the demonstration experiment flavour states (creation and detection eigen states): two states of polarized light e define e mass eigen states (propagation eigen states): two states of polarized light ordinary extraordinary mixing: measure e measure Picture: T. Bode, diploma thesis, University of Münster 7

8 Our birefringent crystals LTB: lithium tetra borate Li2B4O7 wedge angle = 0.2o Laser 001 optical axis 10 mm ( at = nm: ne = no = mm 10 m m 010 from Dr. A. Peter (Research Institute for Solid State Physics and Optics Hungarian Academy of Sciences, Budapest) 8

9 Experimental setup detector 2 analyzer 2 ( polarizer) daq beam splitter detector 1 laserdiode analyzer 1 (as polarizer) polarizer turnable table with two movable bifrigent crystals 9

10 Experimental setup e e/ e 10

11 Changing the oscillations length L wedge angle: 0.2o each crystal moves 5 mm L 38 m osc = 11 m measure position by linear potentiometer 11

12 Changing the mixing angle by turning the crystal table with respect to the polarization directions 12

Conclusions Optical demonstration experiment for 2 flavour neutrino vacuum oscillations with both essential features: - mixing of two microscopic states - coherent propagation (double slit exp.

13 Conclusions Optical demonstration experiment for 2 flavour neutrino vacuum oscillations with both essential features: - mixing of two microscopic states - coherent propagation (double slit exp.) and with: - fully analogical calculation to oscillation - easy variation of mixing angle Experiment can be build with high school or lab class equipment (excluding bifrigent crystals: 100 Euro each) Another demonstration experiment with coupled pendula (with a macroscopic 2 state system): Neutrino pendulum by Michael Kobel et al., TU Dresden ( 13

Experiment 6: Interferometers

Experiment 6: Interferometers Nate Saffold nas2173@columbia.edu Office Hour: Mondays, 5:30PM-6:30PM @ Pupin 1216 INTRO TO EXPERIMENTAL PHYS-LAB 1493/1494/2699 NOTE: No labs and no lecture next week! Outline