Revision 2

Accepted · core change · record

Changes against revision 1:

Title · changed: Revision 1: Is the proton lifetime to $e+ \pi0$ below $1e35\,\mathrm{years}$?; Revision 2: Is the proton lifetime to $e+ \pi0$ below $10^{35}\,\mathrm{years}$?
Plain: Grand unified theories predict a proton can decay into a positron and a neutral pion. Huge water detectors watch for this rare event.
Precise · changed · core: Revision 1: Measure or bound $\tau(p \to e+ \pi0)/B$, currently $> 2.4e34\,\mathrm{yr}$ (Super-Kamiokande, 2020, 90 percent CL). Non-supersymmetric $\mathrm{SO}(10)$ models with intermediate scales typically predict $1e34\text{ to }1e36\,\mathrm{yr}$. An answer is a detection or a limit near $1e35\,\mathrm{yr}$.; Revision 2: Measure or bound $\tau(p \to e+ \pi0)/B$, currently $> 2.4 \times 10^{34}\,\mathrm{yr}$ (Super-Kamiokande, 2020, 90 percent CL). Non-supersymmetric $\mathrm{SO}(10)$ models with intermediate scales typically predict $10^{34}\text{ to }10^{36}\,\mathrm{yr}$. An answer is a detection or a limit near $10^{35}\,\mathrm{yr}$.
Settled by · changed · core: Revision 1: Hyper-Kamiokande exposure of about 1 to 2 Mt-yr reaching $\sim 1\mathrm{e}35\,\mathrm{yr}$ sensitivity.; Revision 2: Hyper-Kamiokande exposure of about 1 to 2 Mt-yr reaching $\sim 10^{35}\,\mathrm{yr}$ sensitivity.
Kind: well-posed
Answer type: yes-no
References: (empty)
Literature status: open
Status note: Hyper-Kamiokande construction is under way, with data expected late in the 2020s.
Posed since: 1974

Decisions