Abstract We correct an overestimation of the production rate of $$^{137}$$ 137 Xe in the DARWIN detector operated at LNGS. This formerly dominant intrinsic background source is now at a level similar ...to the irreducible background from solar $$^8$$ 8 B neutrinos, thus unproblematic at the LNGS depth. The projected half-life sensitivity for the neutrinoless double beta decay ( $$0\nu \beta \beta $$ 0 ν β β ) of $$^{136}$$ 136 Xe improves by $$22\%$$ 22 % compared to the previously reported number and is now $$T^{0\nu }_{1/2}= {3.0\times 10^{27}} \hbox { yr}$$ T 1 / 2 0 ν = 3.0 × 10 27 yr (90% C.L.) after 10 years of DARWIN operation.
Abstract The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of $$^{136}$$ 136 Xe. Out of its 50 t total ...natural xenon inventory, 40 t will be the active target of a time projection chamber which thus contains about 3.6 t of $$^{136}$$ 136 Xe. Here, we show that its projected half-life sensitivity is $$2.4\times {10}^{27}\,{\hbox {year}}$$ 2.4 × 10 27 year , using a fiducial volume of 5 t of natural xenon and 10 year of operation with a background rate of less than 0.2 events/(t $$\cdot $$ · year) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in $$^{136}$$ 136 Xe.
Abstract The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of $$^{136}$$ 136 Xe. Out of its 50 t total ...natural xenon inventory, 40 t will be the active target of a time projection chamber which thus contains about 3.6 t of $$^{136}$$ 136 Xe. Here, we show that its projected half-life sensitivity is $$2.4\times {10}^{27}\,{\hbox {year}}$$ 2.4×1027year , using a fiducial volume of 5 t of natural xenon and 10 year of operation with a background rate of less than 0.2 events/(t $$\cdot $$ · year) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in $$^{136}$$ 136 Xe.
Abstract We correct an overestimation of the production rate of $$^{137}$$ 137 Xe in the DARWIN detector operated at LNGS. This formerly dominant intrinsic background source is now at a level similar ...to the irreducible background from solar $$^8$$ 8 B neutrinos, thus unproblematic at the LNGS depth. The projected half-life sensitivity for the neutrinoless double beta decay ( $$0\nu \beta \beta $$ 0 ν β β ) of $$^{136}$$ 136 Xe improves by $$22\%$$ 22 % compared to the previously reported number and is now $$T^{0\nu }_{1/2}= {3.0\times 10^{27}} \hbox { yr}$$ T 1 / 2 0 ν = 3.0 × 10 27 yr (90% C.L.) after 10 years of DARWIN operation.
Xenon dual-phase time projections chambers (TPCs) have proven to be a successful technology in studying physical phenomena that require low-background conditions. With 40t of liquid xenon (LXe) in ...the TPC baseline design, DARWIN will have a high sensitivity for the detection of particle dark matter, neutrinoless double beta decay (\(0\nu\beta\beta\)), and axion-like particles (ALPs). Although cosmic muons are a source of background that cannot be entirely eliminated, they may be greatly diminished by placing the detector deep underground. In this study, we used Monte Carlo simulations to model the cosmogenic background expected for the DARWIN observatory at four underground laboratories: Laboratori Nazionali del Gran Sasso (LNGS), Sanford Underground Research Facility (SURF), Laboratoire Souterrain de Modane (LSM) and SNOLAB. We determine the production rates of unstable xenon isotopes and tritium due to muon-included neutron fluxes and muon-induced spallation. These are expected to represent the dominant contributions to cosmogenic backgrounds and thus the most relevant for site selection.
Understanding propagation of scintillation light is critical for maximizing the discovery potential of next-generation liquid xenon detectors that use dual-phase time projection chamber technology. ...This work describes a detailed optical simulation of the DARWIN detector implemented using Chroma, a GPU-based photon tracking framework. To evaluate the framework and to explore ways of maximizing efficiency and minimizing the time of light collection, we simulate several variations of the conventional detector design. Results of these selected studies are presented. More generally, we conclude that the approach used in this work allows one to investigate alternative designs faster and in more detail than using conventional Geant4 optical simulations, making it an attractive tool to guide the development of the ultimate liquid xenon observatory.
The LHCb experiment at CERN is undergoing an upgrade in preparation for the Run 3 data taking period of the LHC. As part of this upgrade the trigger is moving to a fully software implementation ...operating at the LHC bunch crossing rate. We present an evaluation of a CPU-based and a GPU-based implementation of the first stage of the High Level Trigger. After a detailed comparison both options are found to be viable. This document summarizes the performance and implementation details of these options, the outcome of which has led to the choice of the GPU-based implementation as the baseline.
We detail the sensitivity of the liquid xenon (LXe) DARWIN observatory to solar neutrinos via elastic electron scattering. We find that DARWIN will have the potential to measure the fluxes of five ...solar neutrino components: \(pp\), \(^7\)Be, \(^{13}\)N, \(^{15}\)O and \(pep\). The precision of the \(^{13}\)N, \(^{15}\)O and \(pep\) components is hindered by the double-beta decay of \(^{136}\)Xe and, thus, would benefit from a depleted target. A high-statistics observation of \(pp\) neutrinos would allow us to infer the values of the weak mixing angle, \(\sin^2\theta_w\), and the electron-type neutrino survival probability, \(P_e\), in the electron recoil energy region from a few keV up to 200 keV for the first time, with relative precision of 5% and 4%, respectively, at an exposure of 300 ty. An observation of \(pp\) and \(^7\)Be neutrinos would constrain the neutrino-inferred solar luminosity down to 0.2%. A combination of all flux measurements would distinguish between the high (GS98) and low metallicity (AGS09) solar models with 2.1-2.5\(\sigma\) significance, independent of external measurements from other experiments or a measurement of \(^8\)B neutrinos through coherent elastic neutrino-nucleus scattering in DARWIN. Finally, we demonstrate that with a depleted target DARWIN may be sensitive to the neutrino capture process of \(^{131}\)Xe.
The DARWIN observatory is a proposed next-generation experiment to search for particle dark matter and for the neutrinoless double beta decay of \(^{136}\)Xe. Out of its 50\(\,\)t total natural xenon ...inventory, 40\(\,\)t will be the active target of a time projection chamber which thus contains about 3.6 t of \(^{136}\)Xe. Here, we show that its projected half-life sensitivity is \(2.4\times10^{27}\,\)yr, using a fiducial volume of 5t of natural xenon and 10\(\,\)yr of operation with a background rate of less than 0.2\(~\)events/(t\(\cdot\)yr) in the energy region of interest. This sensitivity is based on a detailed Monte Carlo simulation study of the background and event topologies in the large, homogeneous target. DARWIN will be comparable in its science reach to dedicated double beta decay experiments using xenon enriched in \(^{136}\)Xe.
Measurement of phi_s at LHCb Hansmann-Menzemer, Stephanie; the LHCb collaboration
arXiv.org,
12/2010
Paper, Journal Article
Odprti dostop
A time dependent angular analysis of the decay mode \(B_s \rightarrow J/\psi \phi\) allows for the measurement of the mixing induced CP-violating phase \(\phi_s\). Within the Standard Model ...\(\phi_s\) is theoretically precisely predicted to be very small, however many Standard Model extensions predict sizeable contributions to this phase. The current experimental knowledge of \(\phi_s\) has very larger uncertainties. However already with the data expected to be delivered within the next year, the LHCb experiment at the Large Hadron Collider at CERN, has the potential to improve significantly existing measurements. In a data set of up to 37.5 pb\(^{-1}\) taken in 2010, first physics signals in the LHCb detector are reconstructed and their properties are compared to Monte Carlo predictions. Based on recently published measurements of \(b\bar{b}\) cross-sections from the LHCb collaboration, the sensitivity on the \(CP\) violating phase \(\phi_s\) in the decay \(B_s \rightarrow J/\psi \phi\) is evaluated. Additionally an alternative method to potentially extract complementary information on \(\phi_s\) from the measurement of the asymmetry in semileptonic final states is presented.
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