Search for Spontaneous Radiation from Wave Function Collapse in the Majorana Demonstrator
The Majorana Demonstrator neutrinoless double-beta decay experiment comprises a 44 kg (30 kg enriched in ^{76}Ge) array of p-type, point-contact germanium detectors. With its unprecedented energy resolution and ultralow backgrounds, Majorana also searches for rare event signatures from beyond standard model physics in the low energy region below 100 keV. In this Letter, we test the continuous spontaneous localization (CSL) model, one of the mathematically well-motivated wave function collapse models aimed at solving the long-standing unresolved quantum mechanical measurement problem. While the CSL predicts the existence of a detectable radiation signature in the x-ray domain, we find no evidence of such radiation in the 19-100 keV range in a 37.5 kg-y enriched germanium exposure collected between December 31, 2015, and November 27, 2019, with the Demonstrator. We explored both the non-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the CSL with two different assumptions: that only the quasifree electrons can emit the x-ray radiation and that the nucleus can coherently emit an amplified radiation. In all cases, we set the most stringent upper limit to date for the white CSL model on the collapse rate, λ, providing a factor of 40-100 improvement in sensitivity over comparable searches. Our limit is the most stringent for large parts of the allowed parameter space. If the result is interpreted in terms of the Diòsi-Penrose gravitational wave function collapse model, the lower bound with a 95% confidence level is almost an order of magnitude improvement over the previous best limit.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Pacific Northwest National Laboratory (PNNL), Richland, WA (United States); Lawrence Berkeley National Laboratory (LBNL), Berkeley, CA (United States); Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); University of North Carolina, Chapel Hill, NC (United States); Duke Univ., Durham, NC (United States). Triangle Universities Nuclear Laboratory
- Sponsoring Organization:
- USDOE Office of Science (SC), Nuclear Physics (NP); USDOE Laboratory Directed Research and Development (LDRD) Program; National Science Foundation (NSF)
- Contributing Organization:
- MAJORANA Collaboration; Majorana Collaboration
- Grant/Contract Number:
- AC02-05CH11231; AC05-00OR22725; AC05-76RL0130; FG02-97ER41020; FG02-97ER41033; FG02-97ER41041; SC0012612; SC0014445; SC0018060; LANLEM77/LANLEM78; MRI-0923142; PHY-1003399; PHY-1102292; PHY-1206314; PHY-1614611; PHY-1812409; PHY-1812356; PHY-2111140; 89233218CNA000001; AC05-76RL01830; PHY1614611; PHY2111140
- OSTI ID:
- 1882003
- Alternate ID(s):
- OSTI ID: 1883666; OSTI ID: 1889981; OSTI ID: 1891100; OSTI ID: 1907284; OSTI ID: 1907656; OSTI ID: 2242467
- Report Number(s):
- LA-UR-22-20042; PNNL-SA-169719; PRLTAO; 080401
- Journal Information:
- Physical Review Letters, Journal Name: Physical Review Letters Vol. 129 Journal Issue: 8; ISSN 0031-9007
- Publisher:
- American Physical SocietyCopyright Statement
- Country of Publication:
- United States
- Language:
- English
Similar Records
Constraints on the Decay of $^{180m}$$\mathrm{Ta}$
Charge trapping correction and energy performance of the Majorana Demonstrator