Indara Suarez

The gp-->etap reaction has been measured with the Crystal Ball and TAPS multiphoton spectrometers in the energy range from the production threshold of 707 MeV to 1.4 GeV (1.49 =< W >= 1.87 GeV). Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz Microtron MAMI-C and momentum analyzed by the Glasgow Tagging Spectrometer were used for the eta-meson production. Our accumulation of 3.8 x 10^6 gp-->etap-->3pi0p-->6gp events allows a detailed study of the reaction dynamics. The gp-->etap differential cross sections were determined for 120 energy bins and the full range of the production angles. Our data show a dip near W = 1680 MeV in the total cross section caused by a substantial dip in eta production at forward angles. The data are compared to predictions of previous SAID and MAID partial-wave analyses and to thelatest SAID and MAID fits that have included our data.

The dynamics of the $\eta\to 3\pi^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5-GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $\eta$-meson production. The analysis of $3 \times 10^6$ $\gamma p \to \eta p \to 3\pi^0 p \to 6\gamma p$ events yields the value $\alpha=-0.032\pm0.003$ for the $\eta\to 3\pi^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The $\pi^0\pi^0$ invariant-mass spectrum was investigated for the occurrence of a cusplike structure in the vicinity of the $\pi^+\pi^-$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.

Measurements of γp→K+Λ and γp→K+Σ0 cross-sections have been obtained with the photon tagging facility and the Crystal Ball calorimeter at MAMI-C. The measurement uses a novel K+ meson identification technique in which the weak decay products are characterized using the energy and timing characteristics of the energy deposit in the calorimeter, a method that has the potential to be applied at many other facilities. The fine center-of-mass energy (W) resolution and statistical accuracy of the new data results in a significant impact on partial wave analyses aiming to better establish the excitation spectrum of the nucleon. The new analyses disfavor a strong role for quark–diquark dynamics in the nucleon.

The Dalitz decay $\ensuremath{\eta}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$ has been measured in the $\ensuremath{\gamma}p\ensuremath{\rightarrow}\ensuremath{\eta}p$ reaction with the Crystal Ball and TAPS multiphoton spectrometers, together with the photon-tagging facility at the Mainz Microtron MAMI. The experimental statistic used in this work is one order of magnitude greater than in any previous measurement of $\ensuremath{\eta}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$. The value obtained for the slope parameter ${\ensuremath{\Lambda}}^{\ensuremath{-}2}$ of the $\ensuremath{\eta}$ transition form factor, ${\ensuremath{\Lambda}}^{\ensuremath{-}2}=(1.95\ifmmode\pm\else\textpm\fi{}0.{15}_{\mathrm{stat}}\ifmmode\pm\else\textpm\fi{}0.{10}_{\mathrm{syst}})$ GeV${}^{\ensuremath{-}2}$, is in good agreement with recent measurements conducted in $\ensuremath{\eta}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$ and $\ensuremath{\eta}\ensuremath{\rightarrow}{\ensuremath{\mu}}^{+}{\ensuremath{\mu}}^{\ensuremath{-}}\ensuremath{\gamma}$ decays, as well as with recent form-factor calculations. The uncertainty obtained in the value of ${\ensuremath{\Lambda}}^{\ensuremath{-}2}$ is lower compared to results from previous measurements of the $\ensuremath{\eta}\ensuremath{\rightarrow}{e}^{+}{e}^{\ensuremath{-}}\ensuremath{\gamma}$ decay.

Total and differential cross-sections for the reaction $\ensuremath \gamma p\rightarrow\pi^0\eta p$ have been measured with the Crystal Ball/TAPS detector using the tagged photon facility at the MAMI C accelerator in Mainz. In the energy range $\ensuremath E_{\gamma} = 0.95\mbox{--}1.4$ GeV the reaction is dominated by the excitation and sequential decay of the $\ensuremath \Delta(1700)D_{33}$ -resonance. Angular distributions measured with high statistics allow us to determine the ratio of hadronic decay widths $\ensuremath \Gamma_{\eta\Delta}/\Gamma_{\pi S_{11}}$ and the ratio of the helicity amplitudes $\ensuremath A_{3/2}/A_{1/2}$ for this resonance.

The gamma p --> pi0 pi0 p reaction has been measured from threshold to 1.4 GeV using the Crystal Ball and TAPS photon spectrometers together with the photon tagging facility at the Mainz Microtron. The experimental results include total and differential cross sections as well as specific angular distributions, which were used to extract partial-wave amplitudes. In particular, the energy region below the D13(1520) resonance was studied.

The Dalitz decay η→γe+e− has been measured using the combined Crystal Ball and TAPS photon detector setup at the electron accelerator MAMI-C. Compared to the most recent transition form-factor measurement in the e+e− channel, statistics have been improved by one order of magnitude. The e+e− invariant mass distribution shows a deviation from the QED prediction for a point-like particle, which can be described by a form-factor. Using the usual monopole transition form-factor parameterization, F(m2)=(1−m2/Λ2)−1, a value of Λ−2=(1.92±0.35(stat)±0.13(syst)) GeV−2 has been determined. This value is in good agreement with a recent measurement of the η Dalitz decay in the μ+μ− channel and with recent form-factor calculations. An improved value of the branching ratio BR(η→γe+e−)=(6.6±0.4(stat)±0.4(syst))⋅10−3 has been determined.

We report the first large-acceptance measurement of polarization transfer from a polarized photon beam to a recoiling nucleon. The measurement pioneers a novel polarimetry technique, which can be applied to many other nuclear and hadron physics experiments. The commissioning reaction of 1H(γ, p)π0 in the range 0.4<Eγ<1.4 GeV validates the technique and provides essential new data to constrain the excitation spectrum of the nucleon.

The circular photon asymmetry for pi0 eta photoproduction on the proton was measured for the first time at the tagged photon facility of the MAMI C accelerator using the Crystal Ball/TAPS photon spectrometer. The experimental results are interpreted within a phenomenological isobar model that confirms the dominant role of the Delta(1700)D33 resonance. The measured asymmetry allows us to identify small contributions from positive-parity resonances via interference terms with the dominant D33 amplitude.

A new measurement of the rare, doubly radiative decay eta->pi^0 gamma gamma was conducted with the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. New data on the dependence of the partial decay width, Gamma(eta->pi^0 gamma gamma), on the two-photon invariant mass squared, m^2(gamma gamma), as well as a new, more precise value for the decay width, Gamma(eta->pi^0 gamma gamma) = (0.33+/-0.03_tot) eV, are based on analysis of 1.2 x 10^3 eta->pi^0 gamma gamma decays from a total of 6 x 10^7 eta mesons produced in the gamma p -> eta p reaction. The present results for dGamma(eta->pi^0 gamma gamma)/dm^2(gamma gamma) are in good agreement with previous measurements and recent theoretical calculations for this dependence.

The g p -> K^0 Sigma^+ reaction has been measured from threshold to Eg=1.45 GeV (W_cm=1.9 GeV) using the Crystal Ball and TAPS multiphoton spectrometers together with the photon tagging facility at the Mainz Microtron MAMI. In the present experiment, this reaction was searched for in the 3pi^0 p final state, by assuming K^0_S -> pi^0 pi^0 and Sigma^+ -> pi^0 p. The experimental results include total and differential cross sections as well as the polarization of the recoil hyperon. The new data significantly improve empirical knowledge about the g p -> K^0 Sigma^+ reaction in the measured energy range. The results are compared to previous measurements and model predictions. It is demonstrated that adding the present g p -> K^0 Sigma^+ results to existing data allowed a better description of this reaction with various models.

Here we correct a factor of 2 missed in one of figures and the corresponding sentence in the text. It does not change any conclusions.Received 13 June 2011DOI:https://doi.org/10.1103/PhysRevC.84.029901©2011 American Physical Society

<strong>Purpose:</strong> To present upgraded versions of MC-GPU and PenEASY Imaging, two open-source Monte Carlo codes for the simulation of radiographic projections and CT. The codes have been extended with the aim of studying breast imaging modalities that rely on the accurate modeling of coherent x-ray scatter. <strong>Methods:</strong> The simulation codes were extended to account for the effect of molecular interference in coherent scattering using experimentally measured molecular interference functions. The validity of the new model was tested experimentally using the Energy Dispersive X-Ray Diffraction (EDXRD) technique with a polychromatic x-ray source and an energy-resolved Germanium detector at a fixed scattering angle. Experiments and simulations of a full field digital mammography system with and without a 1D focused antiscatter grid were conducted for additional validation. The modified MC-GPU code was also used to examine the possibility of characterizing breast cancer within a mathematical breast phantom using the EDXRD technique. <strong>Results:</strong> The measured EDXRD spectra were correctly reproduced by the simulation with the modified code while the previous code using the Independent Atomic Approximation led to large errors in the predicted diffraction spectra. There was good agreement between the simulated and measured rejection factor for the 1D focused antiscatter grid with both models. The simulation study in a whole breast showed that the x-ray scattering profiles of adipose, fibrosis, cancer and benign tissues are differentiable. <strong>Conclusion:</strong> MC-GPU and PENELOPE were successfully extended and validated for accurate modeling of coherent x-ray scatter. The EDXRD technique with pencil-cone geometry in a whole breast was investigated by a simulation study and it was concluded that this technique has potential to characterize breast cancer lesions.

The electronics used in the data readout and triggering system for the Compact Muon Solenoid (CMS) experiment at the Large Hadron Collider (LHC) particle accelerator at CERN are exposed to high radiation levels. This radiation can cause permanent damage to the electronic circuitry, as well as temporary effects such as data corruption induced by Single Event Upsets. Once the High Luminosity LHC (HL-LHC) accelerator upgrades are completed it will have five times higher instantaneous luminosity than LHC, allowing for detection of rare physics processes, new particles and interactions. Tests have been performed to determine the effects of radiation on the electronic components to be used for the Endcap Muon electronics project currently being designed for installation in the CMS experiment in 2013. During these tests the digital components on the test boards were operating with active data readout while being irradiated with 55 MeV protons. In reactor tests, components were exposed to 30 years equivalent levels of neutron radiation expected at the HL-LHC. The highest total ionizing dose (TID) for the muon system is expected at the inner-most portion of the CMS detector, with 8900 rad over ten years. Our results show that Commercial Off-The-Shelf (COTS) components selected for the new electronics will operate reliably in the CMS radiation environment.

A new upper limit of 2.3×10−4 on the branching ratio of the decay ω→ηπ0 has been obtained using the Crystal Ball multiphoton spectrometer at the Mainz Microtron MAMI. This decay is forbidden by charge-conjugation invariance of the strong and electromagnetic interactions. We have also obtained the upper limit of 2.3×10−4 for the forbidden decay ω→3π0 and the upper limit of 2.4×10−4 for ω→2π0.Received 9 December 2008DOI:https://doi.org/10.1103/PhysRevC.79.065201©2009 American Physical Society

The 12C $(\vec{\gamma},pp)$ reaction has been studied in the photon energy range 200-450 MeV at the Mainz microtron MAMI-C, where linearly polarised photons were energy-tagged using the Glasgow-Mainz Tagged Photon Spectrometer and protons were detected in the Crystal Ball detector. The photon asymmetry $\Sigma$ has been measured over a wider $E_{\gamma}$ range than previous measurements. The strongest asymmetries were found at low missing energies where direct emission of nucleon pairs is expected. Cuts on the difference in azimuthal angles of the two ejected protons increased the magnitude of the observed asymmetries. At low missing energies the $\Sigma$ data exhibit a strong angular dependence, similar to deuteron photodisintegration.

El presente estudio expone las percepciones sociales de turistas, pobladores locales, funcionarios de gobierno, observadores de aves, pescadores y productores con relación al manejo, monitoreo, soluciones, responsabilidades y condición de la calidad del agua de la Laguna de Yuriria, Guanajuato. La información se obtuvo mediante entrevistas semiestructuradas y cuestionarios diseñados para aplicarse a distancia debido a la pandemia ocasionada por un nuevo coronavirus (COVID-19). En total, participaron 71 personas. Los datos obtenidos se procesaron a través del programa R para el Análisis de Datos Cualitativos (RQDA) y fueron agrupados en las tres dimensiones del bienestar humano (material, relacional y subjetiva). El 7.05 % del total de los entrevistados consideró que la calidad del agua es buena, el 18.30 % regular, el 42.26 % mala y el 12.67 % muy mala. El 19.72 % desconoció el tema. Los funcionarios consideran que la condición de la calidad del agua se debe a una mala gestión y administración pública. Los observadores de aves advierten que la calidad del agua es mala y que a menor calidad del agua menor biodiversidad de especies. La mayoría de los pescadores considera que la calidad del agua es regular y que la laguna mantiene la economía de sus familias y de las comunidades de La Angostura y Los Tepetates. Estas percepciones ayudaron a obtener un análisis social de la calidad del agua en la laguna y pueden derivar en el reforzamiento y la creación de estrategias para el manejo y la conservación de este cuerpo de agua.

With the forthcoming High Luminosity LHC accelerator upgrade, the CMS Endcap Muon system will require new electronics to handle the increased data rate while maintaining high data collection efficiency. Maintaining trigger efficiency for pseudorapidity above 2.1 requires deployment of higher performance electronics already in 2013. With the increased luminosity, the new electronics will be exposed to substantial radiation levels requiring higher tolerance of the components to radiation. We report on the progress in developing and building the new system and the results of radiation tolerance testing of the commercial components used in the system.

Reproduction in Domestic AnimalsVolume 50, Issue 5 p. i-ii Issue InformationFree Access Issue Information First published: 15 September 2015 https://doi.org/10.1111/rda.12428AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume50, Issue5October 2015Pages i-ii RelatedInformation

Reproduction in Domestic AnimalsVolume 50, Issue 3 p. i-ii Issue InformationFree Access Issue Information First published: 23 April 2015 https://doi.org/10.1111/rda.12426AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume50, Issue3June 2015Pages i-ii RelatedInformation

The total cross section for gamma p -&gt; 3pi0 p has been measured for the first time from threshold to 1.4 GeV using the tagged photon beam of the Mainz Microtron. The equipment utilized the Crystal Ball multiphoton spectrometer, the TAPS forward detector and a particle identification detector. The gamma p -&gt; 3pi0 p total cross section has two broad enhancements at sqrt{s}~1.5 GeV and 1.7 GeV. We obtained the ratio of the total cross sections gamma p -&gt; 3pi0 p to gamma p -&gt; eta p equal to 0.014 \pm 0.001 at sqrt{s}~1.5 GeV.

The dynamics of the $\eta\to 3\pi^0$ decay have been studied with the Crystal Ball multiphoton spectrometer and the TAPS calorimeter. Bremsstrahlung photons produced by the 1.5 GeV electron beam of the Mainz microtron MAMI-C and tagged by the Glasgow photon spectrometer were used for $\eta$-meson production. The analysis of $3 \times 10^6$ $\gamma p \to \eta p \to 3\pi^0 p \to 6\gamma p$ events yields the value $\alpha=-0.032\pm0.003$ for the $\eta\to 3\pi^0$ slope parameter, which agrees with the majority of recent experimental results and has the smallest uncertainty. The $\pi^0\pi^0$ invariant-mass spectrum was investigated for the occurrence of a cusp-like structure in the vicinity of the $\pi^+\pi^-$ threshold. The observed effect is small and does not affect our measured value for the slope parameter.