42639050
Development of New Front-End Electronics for Super-Kamiokande
Super-Kamiokande is a ring imaging water Cherenkov detector for astro-particle physics that consists of 50 kton pure water and about 13000 photomultiplier tubes (PMTs). We are planning to upgrade all the front-end electronics in next year. By high speed signal processing electronics, we will record all the hits of all the PMTs without any hardware filtering, aiming observations of much fainter signals of the supernova relic neutrinos, lower energy (~3 MeV) solar neutrinos, neutrino burst from nearby galactic supernova, and so on. The energy resolutions of multi-GeV atmospheric neutrino events will also be improved by the electronics. The new front-end electronics is based on a charge to time converter (QTC) and a multi-hit TDC. TCP/IP based readout channel is implemented to handle large amounts of data. We have developed a custom ASIC QTC and evaluated the characteristics of the chip and the prototypical board; high-speed (1 MHz cycle), high sensitivity for single photo-electron signal, good charge (0.1 pC RMS) and timing (0.3 ns RMS) responses, and wide charge dynamic range (2500 pC). In this paper, the design and the performance of the front-end board are discribed.
118412548
Mission Design of LiteBIRD
LiteBIRD is a next-generation satellite mission to measure the polarization of the cosmic microwave background (CMB) radiation. On large angular scales the B-mode polarization of the CMB carries the imprint of primordial gravitational waves, and its precise measurement would provide a powerful probe of the epoch of inflation. The goal of LiteBIRD is to achieve a measurement of the characterizing tensor to scalar ratio $$r$$r to an uncertainty of $$\delta r=0.001$$δr=0.001. In order to achieve this goal we will employ a kilo-pixel superconducting detector array on a cryogenically cooled sub-Kelvin focal plane with an optical system at a temperature of 4 K. We are currently considering two detector array options; transition edge sensor (TES) bolometers and microwave kinetic inductance detectors. In this paper we give an overview of LiteBIRD and describe a TES-based polarimeter designed to achieve the target sensitivity of 2 $$\upmu $$μK arcmin over the frequency range 50–320 GHz.
25628512
Measurement of the cosmic microwave background polarization lensing power spectrum with the POLARBEAR experiment.
Gravitational lensing due to the large-scale distribution of matter in the cosmos distorts the primordial cosmic microwave background (CMB) and thereby induces new, small-scale B-mode polarization. This signal carries detailed information about the distribution of all the gravitating matter between the observer and CMB last scattering surface. We report the first direct evidence for polarization lensing based on purely CMB information, from using the four-point correlations of even- and odd-parity E- and B-mode polarization mapped over ∼30 square degrees of the sky measured by the POLARBEAR experiment. These data were analyzed using a blind analysis framework and checked for spurious systematic contamination using null tests and simulations. Evidence for the signal of polarization lensing and lensing B modes is found at 4.2σ (stat+sys) significance. The amplitude of matter fluctuations is measured with a precision of 27%, and is found to be consistent with the Lambda cold dark matter cosmological model. This measurement demonstrates a new technique, capable of mapping all gravitating matter in the Universe, sensitive to the sum of neutrino masses, and essential for cleaning the lensing B-mode signal in searches for primordial gravitational waves.
118598825
A measurement of the cosmic microwave background B-mode polarization power spectrum at sub-degree scales with POLARBEAR
We report a measurement of the B-mode polarization power spectrum in the cosmic microwave background (CMB) using the POLARBEAR experiment in Chile. The faint B-mode polarization signature carries information about the universe's entire history of gravitational structure formation, and the cosmic inflation that may have occurred in the very early universe. Our measurement covers the angular multipole range 500 < ? < 2100 and is based on observations of an effective sky area of 25? with 3.'5 resolution at 150?GHz. On these angular scales, gravitational lensing of the CMB by intervening structure in the universe is expected to be the dominant source of B-mode polarization. Including both systematic and statistical uncertainties, the hypothesis of no B-mode polarization power from gravitational lensing is rejected at 97.2% confidence. The band powers are consistent with the standard cosmological model. Fitting a single lensing amplitude parameter ABB to the measured band powers, , where ABB = 1 is the fiducial WMAP-9 ?CDM value. In this expression, stat refers to the statistical uncertainty, sys to the systematic uncertainty associated with possible biases from the instrument and astrophysical foregrounds, and multi to the calibration uncertainties that have a multiplicative effect on the measured amplitude ABB .
16468601
Hodge duality and cosmological constant
We present a simple mechanism to eliminate cosmological constants both in supersymmetric and non-supersymmetric theories. This mechanism is based on the Hodge (Poincare) duality between a 0-form and D-form field strengths in D-dimensional spacetime. The new key ingredient is the introduction of an extra Chern–Simons term into the D-form field strength H dual to the 0-form field strength. Our formulation can also be made consistent with supersymmetry. Typical applications to four-dimensional N = 1 supergravity and to ten-dimensional type IIA supergravity are given. The success of our formulation for both supersymmetric and non-supersymmetric systems strongly indicates the validity of our mechanism even after supersymmetry breakings at the classical level. Our mechanism may well be applicable to quantized systems, at least for supersymmetric cases with fundamental D-brane actions available.
120111619
$D=2$ Superfield Supergravity, Local (Supersymmetry)**2 and Nonlinear $\sigma$ Models
The authors construct the unconstrained superfield formulation of D=2, N=1 supergravity and give general matter couplings. A new type of non-linear sigma model that possesses (local supersymmetry)(X)(local supersymmetry) is described.
13834469
Topological gauging of N=16 supergravity in three-dimensions
We present a topologically non-trivial generalization of gauged N=16 supergravity on the coset E_8 / SO(16) in three-dimensions. This formulation is based on a combination of BF-term and a Chern-Simons term for an SO(16) gauge field A_\m{}^{I J}. The fact that an additional vector field B_\m{}^{I J} is physical and propagating with couplings to \sigma-model fields makes our new gauging non-trivial and different from the conventional one. Even though the field strength of the A_\m{}^{I J}-field vanishes on-shell, the action is topologically non-trivial due to non-vanishing \pi_3-homotopy. We also present an additional modifications by an extra Chern-Simons term. As by-products, we give also an application to N=9 supergravity coupled to a \sigma-model on the coset F_4 / SO(9), and a new BF-Chern-Simons theory coupled to ^\forall N extended supergravity.
17968925
N = 4 supersymmetric Yang-Mills multiplet in nonadjoint representations
We formulate a theory for an N=4 supersymmetric Yang-Mills multiplet in a nonadjoint representation R of SO(N), as an important application of our recently proposed model for N=1 supersymmetry. This system is obtained by dimensional reduction from an N=1 supersymmetric Yang-Mills multiplet in a nonadjoint representation in ten dimensions. The consistency with supersymmetry requires that a nonadjoint representation R with the indices i,j,... satisfy the three conditions {eta}{sup ij}={delta}{sup ij}, (T{sup I}){sup ij}=-(T{sup I}){sup ji}, and (T{sup I}){sup [ij|}(T{sup I}){sup |k]l}=0 for the metric {eta}{sup ij} and the generators T{sup I}, which are the same as the N=1 case.
119355316
SUPER-LAX OPERATOR EMBEDDED IN SELF-DUAL SUPERSYMMETRIC YANG-MILLS THEORY
We show that the super-Lax operator for N=1 supersymmetric Kadomtsev-Petviashvili (SKP) equation of Manin and Radul in three dimensions can be embedded into recently developed self-dual supersymmetric Yang-Mills theory in 2+2 dimensions, based on general features of its underlying super-Lax equation. The whole hierarchy of the SKP equations of Manin and Radul is generated by geometrical superfield equations of self-dual supersymmetric Yang-Mills theory. The differential geometrical relationship in superspace between the embedding principle of the super-Lax operator and its associated super-Sato equation is clarified. This result provides a good guiding principle for the embedding of other integrable subsystems in the super-Lax equation into the four-dimensional self-dual supersymmetric Yang-Mills theory, which is the consistent background for N=2 superstring theory, and potentially generates other unknown supersymmetric integrable models in lower dimensions.