PVLAS

Collaboration

- INFN: Ferrara, LNL, Padova, Pisa, Trieste

Laboratory: Legnaro National Laboratory of INFN

National Responsible: G. Cantatore (Ts)

1. Goal of the experiment

Several effects, such as photon-photon scattering and particle production from a two-photon interaction, contribute to the complex structure of the quantum vacuum. Pursuing a detection strategy based on optical techniques, these interactions are studied in PVLAS by sending a linearly polarised laser beam through a transverse magnetic field, and by measuring changes in the polarisation state of the light.

More on the experiment...

2.

Activities during 2001

A frequency-doubled laser has been tested in Trieste by achieving frequency-lock to a trial Fabry-Perot cavity. Installation on the main apparatus has however been postponed to 2002, since a signal has already been detected and is now under study. To clarify the nature of this detected signal, 45 hours of actual data acquisition have b,en completed by 31/12/2001

The following achievements have been obtained:

- 45 hours of actual data acquisition

Milestones 2002

Magnetic shielding tests completed. Validation tests on the vibration reduction feedback system | 30-04-2002
Frequency-doubled laser installed at LNL and relative tests completed | 31-08-2002
30 hours of data acquisition with frequency-doubled laser | 31-12-2002

3. INFN contribution to the experiment in terms of manpower and financial support

- Manpower: 11 researchers (7.80 FTE), technical support from Legnaro Laboratories, technical support form the Trieste electronics service
- Budget for the Year 2002: 182.5 kEuro

4. Publications in refereed journals (in 2001): 2

5. Number of talks at conferences (in 2001):

6. Number of undergraduate and doctoral theses on the experiment:

- n. 3 Ph.D. theses
- n. 8 Laurea Diploma theses

7. Leadership roles in the experiment

- E. Zavattini (CERN, INFN and University of Trieste) is the PVLAS senior scientific coordinator
- G. Cantatore (INFN and University of Trieste) is the collaboration spokesman

8. Innovative instruments

- Electro-optic frequency locking system for high-Q, high-Finesse optical resonators.
- Liquid-He rotating cryostat housing a superconducting, high-field, dipole magnet.
- High-sensitivity ellipticity modulator with external control capability based on mechanical stress optical birefringence.

9. Competing experiments

PVLAS is at the moment the only operating experiment in the world having direct access to low energy photon-photon scattering processes.

Main PVLAS technological leads:

- very high Q optical resonators
- liquid He rotating cryostat

10. International committee which has reviewed the experiment

PVLAS is annually reviewed by the INFN National Committee on non-accelerator particle physics