The General Antiparticle Spectrometer (GAPS) is an Antarctic stratospheric balloon mission designed to provide unmatched sensitivity to low-energy (<0.25 GeV/n) cosmic-ray antiprotons, antideuterons, and antihelium nuclei as signatures of dark matter. The distinctive GAPS particle identification technique relies on measuring the energy loss along the track of an incoming antinucleus as it slows down and is captured into an exotic atom, and then detecting the de-excitation X-rays and the nuclear annihilation products. This measurement is realized using a Tracker composed of more than 1000 custom silicon strip detectors and a plastic scintillator time-of-flight (TOF) system instrumenting more than 40m^2. Together, these subsystems provide the velocity and energy resolution, stopping power, particle tracking, and X-ray identification necessary to distinguish rare antinucleus signals from the abundant positive-nucleus backgrounds, all within the constraints of a high-altitude mission. A multi-loop capillary heat pipe system has been developed to maintain the tracker operating temperature with significant mass and power savings over a conventional pump-based system. The first GAPS science payload flew for 25 days during the 2025/26 NASA Antarctic balloon campaign. We detail the design, integration, and commissioning of the payload prior to flight.

LiteBIRD, the Lite (Light) satellite for the study of B-mode polarization and Inflation from cosmic background Radiation Detection, is a space mission for primordial cosmology and fundamental physics. JAXA selected LiteBIRD in May 2019 as a strategic large-class (L-class) mission, with its expected launch in the late 2020s using JAXA's H3 rocket. LiteBIRD plans to map the cosmic microwave background (CMB) polarization over the full sky with unprecedented precision. Its main scientific objective is to carry out a definitive search for the signal from cosmic inflation, either making a discovery or ruling out well-motivated inflationary models. The measurements of LiteBIRD will also provide us with an insight into the quantum nature of gravity and other new physics beyond the standard models of particle physics and cosmology. To this end, LiteBIRD will perform full-sky surveys for three years at the Sun-Earth Lagrangian point L2 for 15 frequency bands between 34 and 448 GHz with three telescopes, to achieve a total sensitivity of 2.16 μK-arcmin with a typical angular resolution of 0.5° at 100 GHz. We provide an overview of the LiteBIRD project, including scientific objectives, mission requirements, top-level system requirements, operation concept, and expected scientific outcomes.

The Balloon-borne Experiment with a Superconducting Spectrometer (BESS) was flown from Lynn Lake, Manitoba, Canada in August, 2000, during the maximum solar modulation period, with an average residual atmospheric overburden of 4.3g/cm2. Precise spectral measurements of cosmic ray hydrogen isotopes from 0.178GeV/n to 1.334GeV/n were made during the 28.7h of flight. This paper presents the measured energy spectra and their ratio, 2H/1H. The results are also compared with previous measurements and theoretical predictions.

The energy spectrum of cosmic-ray antiprotons (p's) from 0.17 to 3.5 GeV has been measured using 7886 p's detected by BESS-Polar II during a long-duration flight over Antarctica near solar minimum in December 2007 and January 2008. This shows good consistency with secondary p calculations. Cosmologically primary p's have been investigated by comparing measured and calculated p spectra. BESS-Polar II data show no evidence of primary p's from the evaporation of primordial black holes.

The Balloon-born Experiment with a Superconducting Spectrometer (BESS), aiming to search for antiparticles/antimatter in the cosmic radiation, successfully carried out the second scientific flight over Antarctica in 2007/2008 (BESS Polar-II), in the solar minimum period. The newly developed BESS Polar-II spectrometer including the solar-cell power supply system worked well during the flight, and more than 4.6 billion cosmic ray events were recorded for 24.5 days. This report describes overview of the scientific flight.

We present a measurement of ${R}_{\mathcal{B}}$, the ratio of the branching fraction for the rare decay ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ to that for the Cabibbo-favored decay ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. Charge-conjugate decays are implicitly included. A signal of $2005\ifmmode\pm\else\textpm\fi{}104$ events for the decay ${D}^{0}\ensuremath{\rightarrow}{K}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ is obtained using the CDF II detector at the Fermilab Tevatron collider. The data set corresponds to an integrated luminosity of $0.35\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ produced in $\overline{p}p$ collisions at $\sqrt{s}=1.96\text{ }\text{ }\mathrm{TeV}$. Assuming no mixing, we find ${R}_{\mathcal{B}}=[4.05\ifmmode\pm\else\textpm\fi{}0.21(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.11(\mathrm{syst})]\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$. This measurement is consistent with the world average, and comparable in accuracy with the best measurements from other experiments.

The GLD is a detector for the experiment at the International Linear Collider (ILC). It consists of a large calorimeter and a gaseous central tracker placed in a moderate magnetic field, both electro-magnetic and hadron calorimeters being placed inside the magnetic coil to have enough hermeticity and good jet energy resolution. The outline of the GLD is presented.

Exclusive dijet production at the Tevatron can be used as a benchmark to establish predictions on exclusive diffractive Higgs production, a process with a much smaller cross section. Exclusive dijet production in Double Pomeron Exchange processes, including diffractive Higgs production with measurements at the Tevatron and predictions for the Large Hadron Collider are presented. Using new data from the Tevatron and dedicated diffractive triggers, no excess over a smooth falling distribution for exclusive dijet events could be found. Upper limits on the exclusive dijet production cross section are presented and compared to current theoretical predictions.

The first scientific flight of the BESS-Polar experiment was carried out in December 2004, aiming at elementary particle phenomena in the early Universe through observation of low energy antiprotons and search for antimatter in the cosmic radiation. The BESS-Polar payload was launched on December 13 from Williams Field near the US McMurdo Station in Antarctica, and circulated around the South Pole for 8 days and 17 hours. During the flight, the superconducting spectrometer including the solar-cell power supply system worked well, and two terabytes scientific data were recorded on the onboard hard disk drives. The flight was terminated on December 21, and the payload landed on the Ross Ice Shelf. The recovery operation continued for a week, and the spectrometer was recovered safely.

We measured atmospheric muon fluxes during ascending (800 – 4 g/cm) and floating (about 5 g/cm) periods of the BESS balloon flight experiments. The observations were carried out at Lynn Lake, Manitoba, Canada in 1999 and 2000 and at Ft. Sumner, New Mexico, USA in 2001. The atmospheric depth dependence on the muon fluxes was clearly observed.

We have carried out a series of atmospheric muon measurements with the BESS spectrometer at various alti- tudes. At the top of Mt. Norikura, Japan (2,770 m above sea level, cutoff rigidity is 11.5 GV), muons at the mountain al- titude were measured very precisely. The observed intensity of atmospheric muons is about 70 % higher than at sea level. During the ascending and floating periods of the balloon ex- periments, the intensity of atmospheric muons was also con- tinuously measured. The muon energy spectra at float alti- tude (5 g=cm 2 ) can provide much useful information about the hadronic interaction models. The measurement of muon growth curve in the atmosphere has been crucially important to calibrate the atmospheric neutrino calculations.

The balloon−borne experiment with a superconducting spectrometer with long duration flights in Antarctica (BESS−Polar) has been progressed. It aims at searches for primordial antiparticles in low− energy cosmic rays with unprecedented sensitivity in the solar minimum period. This report describes the status and future plan of the BESS−Polar experiment.