Fri·May 8, 2015Friday·May 8, 2015

1. 01*

   Results of a search for daily and annual variations of the Po-214 half-life at the two year observation period

   E.N. Alexeyev · Yu.M. Gavrilyuk🇷🇺 · A.M. Gangapshev🇷🇺 · V.V. Kazalov🇷🇺 · V.V. Kuzminov🇷🇺 · S.I. Panasenko🇺🇦 · S.S. Ratkevich🇺🇦

   The brief description of installation TAU-2 intended for long-term monitoring of the half-life value $\tau$ (${\tau }_{1/2}$) of the ${}^{214}$Po is presented. The methods of measurement and processing of collected data are reported. The results of analysis of time series values $\tau$ with different time step are presented. Total of measurement time was equal to 590 days. Averaged value of the ${}^{214}$Po half-life was obtained $\tau =163.46\pm 0.04$ $\mu$s. The annual variation with an amplitude $A=(8.9\pm 2.3)\cdot 10^{-4}$, solar-daily variation with an amplitude $A_{So}=(7.5\pm 1.2)\cdot 10^{-4}$, lunar-daily variation with an amplitude $A_L=(6.9\pm 2.0)\cdot 10^{-4}$ and sidereal-daily variation with an amplitude $A_S=(7.2\pm 1.2)\cdot 10^{-4}$ were found in a series of $\tau$ values. The maximal values of amplitude are observed at the moments when the projections of the installation Earth location velocity vectors toward the source of possible variation achieve its maximal magnitudes.

   nucl-exastro-ph.SRphysics.ins-detPhys.Part.Nucl.(2016)·10 citations
2. 02*

   Extraction of the proton radius from electron-proton scattering data

   Gabriel Lee🇮🇱 · John R. Arrington🇺🇸 · Richard J. Hill🇺🇸

   We perform a new analysis of electron-proton scattering data to determine the proton electric and magnetic radii, enforcing model-independent constraints from form factor analyticity. A wide-ranging study of possible systematic effects is performed. An improved analysis is developed that rebins data taken at identical kinematic settings, and avoids a scaling assumption of systematic errors with statistical errors. Employing standard models for radiative corrections, our improved analysis of the 2010 Mainz A1 Collaboration data yields a proton electric radius $r_E=0.895(20)$ fm and magnetic radius $r_M=0.776(38)$ fm. A similar analysis applied to world data (excluding Mainz data) implies $r_E=0.916(24)$ fm and $r_M=0.914(35)$ fm. The Mainz and world values of the charge radius are consistent, and a simple combination yields a value $r_E=0.904(15)$ fm that is $4\sigma$ larger than the CREMA Collaboration muonic hydrogen determination. The Mainz and world values of the magnetic radius differ by $2.7\sigma$, and a simple average yields $r_M=0.851(26)$ fm. The circumstances under which published muonic hydrogen and electron scattering data could be reconciled are discussed, including a possible deficiency in the standard radiative correction model which requires further analysis.

   ↳ hep-phhep-exnucl-exnucl-th+1PRD(2015)·187 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.