Wed·Jan 17, 2018Wednesday·January 17, 2018

1. 01*

   CompEx II: A Pathway in Search of BSM Physics using Compton Scattering

   Prajwal Mohanmurthy🇺🇸 · Dipangkar Dutta🇺🇸

   Constancy and anisotropy of vacuum refractive index serves as a strong way to probe the predictions of theories beyond the standard model (BSM), especially those that predict breaking of local Lorentz and CPT symmetries. For photons of energies in the ranges $9-46$ MeV using a $1.16$ GeV electron beam, a constraint on vacuum refractive index, $(n-1)<1.4\times 10^{-8}$ was imposed using the Compton polarimeter in Hall - C of Jefferson Lab (JLab). Absence of sidereal modulation of the vacuum refractive index was then used to constrain the Minimal Standard Model Extension (MSME) parameters of $\sqrt{{\kappa }_X^2+{\kappa }_Y^2}<8.6\times 10^{-10}$. These preliminary set of measurements will be followed up by measurements using the $11$ GeV electron beam at JLab with a sensitivity better than current leading constraints by a factor of $4-8$. Furthermore, quantum gravity models predict crystalline nature of space at Planck scales which may manifest as vacuum birefringence that can be probed by Compton scattering using circularly polarized light. We show that future facilities such as the ILC provide tantalizingly interesting possibilities.

   nucl-ex1 citation
2. 02*

   Lifetime measurement of the ${}^{229}$Th nuclear isomer

   Benedict Seiferle · Lars von der Wense · Peter G. Thirolf🇩🇪

   The first excited isomeric state of ${}^{229}$Th possesses the lowest energy among all known excited nuclear states. The expected energy is accessible with today's laser technology and in principle allows for a direct optical laser excitation of the nucleus. The isomer decays via three channels to its ground-state (internal conversion, $\gamma$ decay and bound internal conversion), whose strengths depend on the charge state of ${}^{229m}$Th. We report on the measurement of the internal-conversion decay half-life of neutral ${}^{229m}$Th. A half-life of 7 $\pm$ 1 $\mu$s has been measured, which is in the range of theoretical predictions and, based on the theoretically expected lifetime of $\approx 10^4$ s of the photonic decay channel, gives further support for an internal conversion coefficient of $\approx 10^9$, thus constraining the strength of a radiative branch in the presence of IC.

   nucl-exPRL(2017)·96 citations
3. 03*

   Light-Meson Spectroscopy at GlueX

   A. Austregesilo (for the GlueX collaboration)🇺🇸

   GlueX at Jefferson Lab aims to study the light meson spectrum with an emphasis on the search for light hybrid mesons. To this end, a linearly-polarized $9$GeV photon beam impinges on a hydrogen target contained within a hermetic detector with near-complete neutral and charged particle coverage. In 2016, the experiment completed its commissioning and subsequently started to take data in its design configuration. With the size of the data set so far, GlueX already exceeds previous experiments for polarized photoproduction in this energy regime. A selection of early results will be presented, focusing on beam asymmetries for pseudo-scalar and vector mesons. The potential to make significant contributions to the field of light-meson spectroscopy is highlighted by the observation of several known meson resonances. Furthermore, the strategy to map the light meson spectrum with amplitude analysis tools will be outlined.

   nucl-exhep-exInt.J.Mod.Phys.Conf.Ser.(2018)·16 citations
4. 04*

   Study of Rare Nuclear Processes with CUORE

   CUORE Collaboration: C. Alduino🇺🇸 · K. Alfonso🇺🇸 · F. T. Avignone III🇺🇸 · O. Azzolini🇮🇹 · G. Bari🇮🇹 · F. Bellini🇮🇹 · G. Benato🇺🇸 · A. Bersani🇮🇹 · M. Biassoni🇮🇹 · A. Branca🇮🇹 · C. Brofferio🇮🇹 · C. Bucci🇮🇹 and 106 other authors

   TeO2 bolometers have been used for many years to search for neutrinoless double beta decay in 130-Te. CUORE, a tonne-scale TeO2 detector array, recently published the most sensitive limit on the half-life, $T_{1/2}^{0\nu }>1.5\times 10^{25}$yr, which corresponds to an upper bound of $140-400$~meV on the effective Majorana mass of the neutrino. While it makes CUORE a world-leading experiment looking for neutrinoless double beta decay, it is not the only study that CUORE will contribute to in the field of nuclear and particle physics. As already done over the years with many small-scale experiments, CUORE will investigate both rare decays (such as the two-neutrino double beta decay of 130-Te and the hypothesized electron capture in 123-Te), and rare processes (e.g., dark matter and axion interactions). This paper describes some of the achievements of past experiments that used TeO2 bolometers, and perspectives for CUORE.

   nucl-exphysics.ins-detInt.J.Mod.Phys.A(2018)·14 citations
5. 05*

   Demonstration of a Sensitive Method to Measure Nuclear Spin-Dependent Parity Violation

   Emine Altuntas · Jeffrey Ammon · Sidney B. Cahn🇺🇸 · David DeMille🇺🇸

   Nuclear spin-dependent parity violation (NSD-PV) effects in atoms and molecules arise from $Z^0$ boson exchange between electrons and the nucleus, and from the magnetic interaction between electrons and the parity-violating nuclear anapole moment. We demonstrate measurements of NSD-PV that use an enhancement of the effect in diatomic molecules, here using the test system ${}^{138}$Ba${}^{19}$F. Our sensitivity surpasses that of any previous atomic PV measurement. We show that systematic errors can be suppressed to at least the level of the present statistical sensitivity. We measure the matrix element, $W$, of the NSD-PV interaction with total uncertainty $\delta W/(2\pi )<0.7$ Hz, for each of two configurations where $W$ must have different signs. This sensitivity would be sufficient to measure NSD-PV effects of the size anticipated across a wide range of nuclei.

   ↳ physics.atom-phnucl-exPRL(2018)·70 citations
6. 06*

   Physics with Reactor Neutrinos

   Xin Qian🇺🇸 · Jen-Chieh Peng🇺🇸

   Neutrinos produced by nuclear reactors have played a major role in advancing our knowledge of the properties of neutrinos. The first direct detection of the neutrino, confirming its existence, was performed using reactor neutrinos. More recent experiments utilizing reactor neutrinos have also found clear evidence for neutrino oscillation, providing unique input for the determination of neutrino mass and mixing. Ongoing and future reactor neutrino experiments will explore other important issues, including the neutrino mass hierarchy and the search for sterile neutrinos and other new physics beyond the standard model. In this article, we review the recent progress in physics using reactor neutrinos and the opportunities they offer for future discoveries.

   ↳ hep-exhep-phnucl-exRept.Prog.Phys.(2019)·57 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.