This content will become publicly available on February 8, 2025
The precision in reconstructing events detected in a dualphase time projection chamber depends on an homogeneous and well understood electric field within the liquid target. In the XENONnT TPC the field homogeneity is achieved through a doublearray field cage, consisting of two nested arrays of field shaping rings connected by an easily accessible resistor chain. Rather than being connected to the gate electrode, the topmost field shaping ring is independently biased, adding a degree of freedom to tune the electric field during operation. Twodimensional finite element simulations were used to optimize the field cage, as well as its operation. Simulation results were compared to
 NSFPAR ID:
 10515699
 Author(s) / Creator(s):
 ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; ; more »
 Publisher / Repository:
 The European Physical Journal C
 Date Published:
 Journal Name:
 The European Physical Journal C
 Volume:
 84
 Issue:
 2
 ISSN:
 14346052
 Format(s):
 Medium: X
 Sponsoring Org:
 National Science Foundation
More Like this

Noble element time projection chambers are a leading technology for rare event detection in physics, such as for dark matter and neutrinoless double beta decay searches. Time projection chambers typically assign event position in the drift direction using the relative timing of prompt scintillation and delayed charge collection signals, allowing for reconstruction of an absolute position in the drift direction. In this paper, alternate methods for assigning event drift distance via quantification of electron diffusion in a pure high pressure xenon gas time projection chamber are explored. Data from the NEXTWhite detector demonstrate the ability to achieve good position assignment accuracy for both high and lowenergy events. Using pointlike energy deposits frommore » « less
Kr calibration electron captures ($$^{83\textrm{m}}$$ ${}^{83\text{m}}$ keV), the position of origin of lowenergy events is determined to 2 cm precision with bias$$E\sim 45$$ $E\sim 45$ mm. A convolutional neural network approach is then used to quantify diffusion for longer tracks ($$< 1~$$ $<1\phantom{\rule{0ex}{0ex}}$ MeV), from radiogenic electrons, yielding a precision of 3 cm on the event barycenter. The precision achieved with these methods indicates the feasibility energy calibrations of better than 1% FWHM at Q$$E\ge ~1.5$$ $E\ge \phantom{\rule{0ex}{0ex}}1.5$ in pure xenon, as well as the potential for event fiducialization in large future detectors using an alternate method that does not rely on primary scintillation.$$_{\beta \beta }$$ ${}_{\beta \beta}$ 
Abstract We present a proof of concept for a spectrally selective thermal midIR source based on nanopatterned graphene (NPG) with a typical mobility of CVDgrown graphene (up to 3000
), ensuring scalability to large areas. For that, we solve the electrostatic problem of a conducting hyperboloid with an elliptical wormhole in the presence of an$$\hbox {cm}^2\,\hbox {V}^{1}\,\hbox {s}^{1}$$ ${\text{cm}}^{2}\phantom{\rule{0ex}{0ex}}{\text{V}}^{1}\phantom{\rule{0ex}{0ex}}{\text{s}}^{1}$inplane electric field. The localized surface plasmons (LSPs) on the NPG sheet, partially hybridized with graphene phonons and surface phonons of the neighboring materials, allow for the control and tuning of the thermal emission spectrum in the wavelength regime from to 12$$\lambda =3$$ $\lambda =3$ m by adjusting the size of and distance between the circular holes in a hexagonal or square lattice structure. Most importantly, the LSPs along with an optical cavity increase the emittance of graphene from about 2.3% for pristine graphene to 80% for NPG, thereby outperforming stateoftheart pristine graphene light sources operating in the nearinfrared by at least a factor of 100. According to our COMSOL calculations, a maximum emission power per area of$$\upmu$$ $\mu $ W/$$11\times 10^3$$ $11\times {10}^{3}$ at$$\hbox {m}^2$$ ${\text{m}}^{2}$ K for a bias voltage of$$T=2000$$ $T=2000$ V is achieved by controlling the temperature of the hot electrons through the Joule heating. By generalizing Planck’s theory to any grey body and deriving the completely general nonlocal fluctuationdissipation theorem with nonlocal response of surface plasmons in the random phase approximation, we show that the coherence length of the graphene plasmons and the thermally emitted photons can be as large as 13$$V=23$$ $V=23$ m and 150$$\upmu$$ $\mu $ m, respectively, providing the opportunity to create phased arrays made of nanoantennas represented by the holes in NPG. The spatial phase variation of the coherence allows for beamsteering of the thermal emission in the range between$$\upmu$$ $\mu $ and$$12^\circ$$ ${12}^{\circ}$ by tuning the Fermi energy between$$80^\circ$$ ${80}^{\circ}$ eV and$$E_F=1.0$$ ${E}_{F}=1.0$ eV through the gate voltage. Our analysis of the nonlocal hydrodynamic response leads to the conjecture that the diffusion length and viscosity in graphene are frequencydependent. Using finitedifference time domain calculations, coupled mode theory, and RPA, we develop the model of a midIR light source based on NPG, which will pave the way to graphenebased optical midIR communication, midIR color displays, midIR spectroscopy, and virus detection.$$E_F=0.25$$ ${E}_{F}=0.25$ 
Abstract The elliptic flow
of$$(v_2)$$ $\left({v}_{2}\right)$ mesons from beautyhadron decays (nonprompt$${\textrm{D}}^{0}$$ ${\text{D}}^{0}$ was measured in midcentral (30–50%) Pb–Pb collisions at a centreofmass energy per nucleon pair$${\textrm{D}}^{0})$$ ${\text{D}}^{0})$ TeV with the ALICE detector at the LHC. The$$\sqrt{s_{\textrm{NN}}} = 5.02$$ $\sqrt{{s}_{\text{NN}}}=5.02$ mesons were reconstructed at midrapidity$${\textrm{D}}^{0}$$ ${\text{D}}^{0}$ from their hadronic decay$$(y<0.8)$$ $\left(\righty<0.8)$ , in the transverse momentum interval$$\mathrm {D^0 \rightarrow K^\uppi ^+}$$ ${D}^{0}\to {K}^{}{\pi}^{+}$ GeV/$$2< p_{\textrm{T}} < 12$$ $2<{p}_{\text{T}}<12$c . The result indicates a positive for nonprompt$$v_2$$ ${v}_{2}$ mesons with a significance of 2.7$${{\textrm{D}}^{0}}$$ ${\text{D}}^{0}$ . The nonprompt$$\sigma $$ $\sigma $ meson$${{\textrm{D}}^{0}}$$ ${\text{D}}^{0}$ is lower than that of prompt nonstrange D mesons with 3.2$$v_2$$ ${v}_{2}$ significance in$$\sigma $$ $\sigma $ , and compatible with the$$2< p_\textrm{T} < 8~\textrm{GeV}/c$$ $2<{p}_{\text{T}}<8\phantom{\rule{0ex}{0ex}}\text{GeV}/c$ of beautydecay electrons. Theoretical calculations of beautyquark transport in a hydrodynamically expanding medium describe the measurement within uncertainties.$$v_2$$ ${v}_{2}$ 
Abstract We introduce a family of Finsler metrics, called the
Fisher–Rao metrics$$L^p$$ ${L}^{p}$ , for$$F_p$$ ${F}_{p}$ , which generalizes the classical Fisher–Rao metric$$p\in (1,\infty )$$ $p\in (1,\infty )$ , both on the space of densities$$F_2$$ ${F}_{2}$ and probability densities$${\text {Dens}}_+(M)$$ ${\text{Dens}}_{+}\left(M\right)$ . We then study their relations to the Amari–C̆encov$${\text {Prob}}(M)$$ $\text{Prob}\left(M\right)$ connections$$\alpha $$ $\alpha $ from information geometry: on$$\nabla ^{(\alpha )}$$ ${\nabla}^{\left(\alpha \right)}$ , the geodesic equations of$${\text {Dens}}_+(M)$$ ${\text{Dens}}_{+}\left(M\right)$ and$$F_p$$ ${F}_{p}$ coincide, for$$\nabla ^{(\alpha )}$$ ${\nabla}^{\left(\alpha \right)}$ . Both are pullbacks of canonical constructions on$$p = 2/(1\alpha )$$ $p=2/(1\alpha )$ , in which geodesics are simply straight lines. In particular, this gives a new variational interpretation of$$L^p(M)$$ ${L}^{p}\left(M\right)$ geodesics as being energy minimizing curves. On$$\alpha $$ $\alpha $ , the$${\text {Prob}}(M)$$ $\text{Prob}\left(M\right)$ and$$F_p$$ ${F}_{p}$ geodesics can still be thought as pullbacks of natural operations on the unit sphere in$$\nabla ^{(\alpha )}$$ ${\nabla}^{\left(\alpha \right)}$ , but in this case they no longer coincide unless$$L^p(M)$$ ${L}^{p}\left(M\right)$ . Using this transformation, we solve the geodesic equation of the$$p=2$$ $p=2$ connection by showing that the geodesic are pullbacks of projections of straight lines onto the unit sphere, and they always cease to exists after finite time when they leave the positive part of the sphere. This unveils the geometric structure of solutions to the generalized Proudman–Johnson equations, and generalizes them to higher dimensions. In addition, we calculate the associate tensors of$$\alpha $$ $\alpha $ , and study their relation to$$F_p$$ ${F}_{p}$ .$$\nabla ^{(\alpha )}$$ ${\nabla}^{\left(\alpha \right)}$ 
Abstract A search for exotic decays of the Higgs boson (
) with a mass of 125$$\text {H}$$ $\text{H}$ to a pair of light pseudoscalars$$\,\text {Ge}\hspace{.08em}\text {V}$$ $\phantom{\rule{0ex}{0ex}}\text{Ge}\phantom{\rule{0ex}{0ex}}\text{V}$ is performed in final states where one pseudoscalar decays to two$$\text {a}_{1} $$ ${\text{a}}_{1}$ quarks and the other to a pair of muons or$${\textrm{b}}$$ $\text{b}$ leptons. A data sample of proton–proton collisions at$$\tau $$ $\tau $ corresponding to an integrated luminosity of 138$$\sqrt{s}=13\,\text {Te}\hspace{.08em}\text {V} $$ $\sqrt{s}=13\phantom{\rule{0ex}{0ex}}\text{Te}\phantom{\rule{0ex}{0ex}}\text{V}$ recorded with the CMS detector is analyzed. No statistically significant excess is observed over the standard model backgrounds. Upper limits are set at 95% confidence level ($$\,\text {fb}^{1}$$ $\phantom{\rule{0ex}{0ex}}{\text{fb}}^{1}$ ) on the Higgs boson branching fraction to$$\text {CL}$$ $\text{CL}$ and to$$\upmu \upmu \text{ b } \text{ b } $$ $\mu \mu \phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}$ via a pair of$$\uptau \uptau \text{ b } \text{ b },$$ $\tau \tau \phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}},$ s. The limits depend on the pseudoscalar mass$$\text {a}_{1} $$ ${\text{a}}_{1}$ and are observed to be in the range (0.17–3.3)$$m_{\text {a}_{1}}$$ ${m}_{{\text{a}}_{1}}$ and (1.7–7.7)$$\times 10^{4}$$ $\times {10}^{4}$ in the$$\times 10^{2}$$ $\times {10}^{2}$ and$$\upmu \upmu \text{ b } \text{ b } $$ $\mu \mu \phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}$ final states, respectively. In the framework of models with two Higgs doublets and a complex scalar singlet (2HDM+S), the results of the two final states are combined to determine upper limits on the branching fraction$$\uptau \uptau \text{ b } \text{ b } $$ $\tau \tau \phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}$ at 95%$${\mathcal {B}}(\text {H} \rightarrow \text {a}_{1} \text {a}_{1} \rightarrow \ell \ell \text{ b } \text{ b})$$ $B(\text{H}\to {\text{a}}_{1}{\text{a}}_{1}\to \ell \ell \phantom{\rule{0ex}{0ex}}\text{b}\phantom{\rule{0ex}{0ex}}\phantom{\rule{0ex}{0ex}}\text{b})$ , with$$\text {CL}$$ $\text{CL}$ being a muon or a$$\ell $$ $\ell $ lepton. For different types of 2HDM+S, upper bounds on the branching fraction$$\uptau $$ $\tau $ are extracted from the combination of the two channels. In most of the Type II 2HDM+S parameter space,$${\mathcal {B}}(\text {H} \rightarrow \text {a}_{1} \text {a}_{1} )$$ $B(\text{H}\to {\text{a}}_{1}{\text{a}}_{1})$ values above 0.23 are excluded at 95%$${\mathcal {B}}(\text {H} \rightarrow \text {a}_{1} \text {a}_{1} )$$ $B(\text{H}\to {\text{a}}_{1}{\text{a}}_{1})$ for$$\text {CL}$$ $\text{CL}$ values between 15 and 60$$m_{\text {a}_{1}}$$ ${m}_{{\text{a}}_{1}}$ .$$\,\text {Ge}\hspace{.08em}\text {V}$$ $\phantom{\rule{0ex}{0ex}}\text{Ge}\phantom{\rule{0ex}{0ex}}\text{V}$