| NSF Org: |
PHY Division Of Physics |
| Recipient: |
|
| Initial Amendment Date: | August 23, 2021 |
| Latest Amendment Date: | September 30, 2022 |
| Award Number: | 2110705 |
| Award Instrument: | Standard Grant |
| Program Manager: |
Nigel Sharp
nsharp@nsf.gov (703)292-4905 PHY Division Of Physics MPS Directorate for Mathematical and Physical Sciences |
| Start Date: | September 1, 2021 |
| End Date: | August 31, 2024 (Estimated) |
| Total Intended Award Amount: | $500,000.00 |
| Total Awarded Amount to Date: | $500,000.00 |
| Funds Obligated to Date: |
|
| History of Investigator: |
|
| Recipient Sponsored Research Office: |
1523 UNION RD RM 207 GAINESVILLE FL US 32611-1941 (352)392-3516 |
| Sponsor Congressional District: |
|
| Primary Place of Performance: |
1 UNIVERSITY OF FLORIDA GAINESVILLE FL US 32611-2002 |
| Primary Place of
Performance Congressional District: |
|
| Unique Entity Identifier (UEI): |
|
| Parent UEI: |
|
| NSF Program(s): | Particle Astrophysics/Undergro |
| Primary Program Source: |
|
| Program Reference Code(s): |
|
| Program Element Code(s): |
|
| Award Agency Code: | 4900 |
| Fund Agency Code: | 4900 |
| Assistance Listing Number(s): | 47.049 |
ABSTRACT
Astronomical observations have established that the Universe is largely dark, with approximately 85% of the matter made of yet unknown particles. Determining the nature of this dark matter will impact our fundamental knowledge of cosmology, astrophysics and particle physics and is the basis for one of the most extensive searches for new physics beyond the Standard Model that has been so effective in describing our understanding to date. Extensions of the Standard Model predict weakly interacting light (sub-electronvolt) particles, including axions, which have been introduced as a primary candidate for the dark matter. The Any Light Particle Search (ALPS) II experiment is designed to provide the highest search sensitivity for these low-mass particles of any measurements to date that use the Light Shining Through a Wall (LSW) technique. Located at DESY in Hamburg, Germany, the ALPS II detector is now under construction and this award supports the ALPS II group at the University of Florida to perform the upcoming commissioning and science runs using the heterodyne detection scheme developed by the team. The experiment provides a unique and diverse training ground for postdoctoral and student researchers to develop skills in electronics and feedback control systems, vacuum and cryogenics, computational methods and data analysis algorithms, large-scale detector commission and operation, and dark matter physics and cosmology.
The ALPS experiment is designed to search for interactions that turn photons into low-mass particles and vice versa, allowing photons to reemerge behind an otherwise light tight wall. These low-mass particles include axion-like particles, their scalar counterparts, as well as hidden sector photons, and would contribute or even exclusively form the omnipresent dark matter. The ALPS II experiment consists of two 120 m long strings of straightened 5.3 T HERA dipoles on each side of the wall. An optical cavity is used to build up the power to up to 1 MW on one side of the wall while a second cavity amplifies the recreation process on the other side of the wall. In contrast to helioscopes and also haloscopes used also in the search for axion-like particles, ALPS makes no assumptions about stellar evolution; nor does it assume any specific dark matter model. The experiment only depends on proposed fundamental interactions between photons and postulated non-standard-model particles. The ALPS II experiment will surpass past LSW searches by 12 orders of magnitude in regenerated photons and explores a parameter space which has lately been favored by astronomical and other observations.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
PUBLICATIONS PRODUCED AS A RESULT OF THIS RESEARCH
Note:
When clicking on a Digital Object Identifier (DOI) number, you will be taken to an external
site maintained by the publisher. Some full text articles may not yet be available without a
charge during the embargo (administrative interval).
Some links on this page may take you to non-federal websites. Their policies may differ from
this site.
PROJECT OUTCOMES REPORT
Disclaimer
This Project Outcomes Report for the General Public is displayed verbatim as submitted by the Principal Investigator (PI) for this award. Any opinions, findings, and conclusions or recommendations expressed in this Report are those of the PI and do not necessarily reflect the views of the National Science Foundation; NSF has not approved or endorsed its content.
The ALPS project is the leading model-independent search for axions and axion-like particles. It relyies on the photo-axion interaction caused by a strong static magnetic field. ALPS is a light-shining-through-the-wall (LSW) experiment in which a minuscule fraction of photons is transformed into these non-standard model particles on one side of the wall. These particles then travel through the opaque wall to the other side where again a minuscule fraction is turned back into a few detectable photons. The experiment can also search for scalar counterparts to the axion and for hidden-sector photons. The discovery of any of these non-standard model interactions would be a critically important discovery and provide the first experimental confirmation of dark matter beyond its gravitational signature.
The Florida group is the only US-based and the second-largest group in the ALPS collaboration; only the ALPS DESY group is larger. DESY is responsible for the infrastructure including the magnets, vacuum system, clean rooms, and most digital data acquisition and signal processing systems as well as system engineering. Florida is responsible for the first interferometric detection system—the heterodyne detection system (HET)—and the subsequent data analysis procedures. We also support the development of the second detection system, which will use a superconducting transition edge sensor (TES).
The first ALPS science run began in March 2023. Already, preliminary analysis shows a 30-fold improvement in the LSW limits on the coupling of axions to two photons. Continuing ALPS commissioning and observations may lead to a direct detection or to upper limits improved by another factor of 30 from the first results.
The major increase in sensitivity is due to two factors. First, the magnetic field on each side of the wall is 120 m long. Previous experiments were 5 to 10 meters long. Second ALPS II uses Fabry-Perot cavities resonant at the laser wavelength in both magnet strings. The resonance builds up the light on the front of the wall and therefore generates more axions or axion-like particles. On the back side, the resonance enhances the regeneration of photons from the axions. The first science run had only the cavity on the regeneration side installed. Future runs will employ both cavities.
Last Modified: 11/25/2024
Modified by: David B Tanner
Please report errors in award information by writing to: awardsearch@nsf.gov.
