The HERA-B Ring Imaging Cherenkov Counter

The HERA-B RICH uses a radiation path length of 2.8 m in C_4F_10 gas and a large 24 square meters spherical mirror for imaging Cherenkov rings. The photon detector consists of 2240 Hamamatsu multi-anode photomultipliers with about 27000 channels. A 2:1 reducing two-lens telescope in front of each PMT increases the sensitive area at the expense of increased pixel size, resulting in a contribution to the resolution which roughly matches that of dispersion. The counter was completed in January of 1999, and its performance has been steady and reliable over the years it has been in operation. The design performance of the RICH was fully reached: the average number of detected photons in the RICH for a beta=1 particle was found to be 33 with a single hit resolution of 0.7 mrad and 1 mrad in the fine and coarse granularity regions, respectively.Comment: 29 pages, 23 figure

The effect of soil conditioner on the spatial variability of soil environment

ArticleThe aim of the study was to assess and evaluate the effect of soil conditioner on the spatial variability of soil environment. Activator PRP-SOL conditioning soil properties was selected as a field of study. Assessment of soil environment was done through the evaluation of selected soil properties, namely, tensile resistance of the soil and soil infiltration ability. Two dose of PRP-SOL application was done twice in year 2015 (Autumn and Spring) and once in 2016 (Spring) with application rates 150 kg ha-1 and 140 kg ha-1 , respectively. The area was divided into blocks where stimulators were applied and none treated as a control. The evaluation of recorded values showed that treatability and tillage itself was significantly better on the area which was treated by application of PRP-SOL activators. In addition, tensile resistance was decreased by 5.71% in comparison with non-treated area of experimental field. Since the infiltration ability is among the very important soil properties which have an effect on soil moisture regime as well as surface runoff and therefore soil erosion. The evaluation of recorded values has revealed the effect of treatment by PRP-SOL activators on soil infiltration ability and therefore it results in increases infiltration of precipitation as well. Overall increase of infiltration was recorded at value 2 mm h -1 . It can be concluded that application of soil activators may increase the soil conditions and therefore not only conserve soil fertility but even increase it from the long term perspective

LAPPD operation using ToFPETv2 PETSYS ASIC

Single photon sensitive detectors used in high energy physics are, in some applications, required to cover very large areas, and more specifically in very strong demand with an ever finer imaging and timing capability for Cherenkov Ring Imaging Detector (RICH) configurations. We are evaluating the Large Area Picosecond Photo-detector (LAPPD) produced by INCOM company, as a possible candidate for future RICH detector upgrades. In this work we perform tests on the first generation device, which is capacitively coupled to a custom designed anode back plane, consisting of various pixels and strips varying in size, that allows for connecting various readout systems such as standard laboratory equipment, as well as the TOFPET2 ASIC from PETsys company [2]. Our aim is to evaluate what can be achieved by merging currently available technology, in order to find directions for future developments adapted for specific uses.Comment: Twepp 2022 workshop proceeding

A novel type of proximity focusing RICH counter with multiple refractive index aerogel radiator

A proximity focusing ring imaging Cherenkov detector, with the radiator consisting of two or more aerogel layers of different refractive indices, has been tested in 1-4 GeV/c pion beams at KEK. Essentially, a multiple refractive index aerogel radiator allows for an increase in Cherenkov photon yield on account of the increase in overall radiator thickness, while avoiding the simultaneous degradation in single photon angular resolution associated with the increased uncertainty of the emission point. With the refractive index of consecutive layers suitably increasing in the downstream direction, one may achieve overlapping of the Cherenkov rings from a single charged particle. In the opposite case of decreasing refractive index, one may obtain well separated rings. In the former combination an approximately 40% increase in photon yield is accompanied with just a minor degradation in single photon angular resolution. The impact of this improvement on the pion/kaon separation at the upgraded Belle detector is discussed.Comment: submitted to Nucl. Instr. Meth.

Readout ASICs and Electronics for the 144-channel HAPDs for the Aerogel RICH at Belle II

AbstractThe particle identification (PID) device in the endcap of the Belle detector will be upgraded to a ring imaging Cherenkov counter (RICH) using aerogel as a radiator at the Belle II experiment. We develop the electronics to read out the 70,000 channels of hit information from the 144-channel hybrid avalanche photodetectors (HAPD), of the aerogel RICH detector. A readout ASIC is developed to digitize the HAPD signals, and was used in a beam test with the prototype detector. The performance and plan of the ASIC is reported in this study. We have also designed the readout electronics for the aerogel RICH, which consist of front-end boards with the ASICs merger boards to collect data from the front-end boards. A front-end board that fits in the actual available space for the aerogel RICH electronics was produced

Observation of Bs->Ds(*)+Ds(*)- using e+e- collisions and a determination of the Bs-Bsbar width difference \Delta\Gamma_s

We have made the first observation of Bs->Ds(*)+Ds(*)- decays using 23.6 fb-1 of data recorded by the Belle experiment running on the Upsilon(5S) resonance. The branching fractions are measured to be B(B^0_s\ra D^+_s D^-_s) = (1.0\,^{+0.4}_{-0.3}\,^{+0.3}_{-0.2})%, B(B^0_s\ra D^{*\pm}_s D^{\mp}_s) = (2.8\,^{+0.8}_{-0.7}\,\pm 0.7)%, and B(B^0_s\ra D^{*+}_s D^{*-}_s) = (3.1\,^{+1.2}_{-1.0}\,\pm 0.8)%; the sum is B(B^0_s\ra D^{(*)+}_s D^{(*)-}_s) = (6.9\,^{+1.5}_{-1.3}\,\pm 1.9)%. Assuming Bs->Ds(*)+Ds(*)- saturates decays to CP-even final states, the branching fraction determines the ratio \Delta\Gamma_s/cos(\phi), where \Delta\Gamma_s is the difference in widths between the two Bs-Bsbar mass eigenstates, and \phi is a CP-violating weak phase. Taking CP violation to be negligibly small, we obtain \Delta\Gamma_s/\Gamma_s = 0.147^{+0.036}_{-0.030}(stat.)^{+0.044}_{-0.042}(syst.), where \Gamma_s is the mean decay width.Comment: 13 pages, 2 figures, 2 tables. v2: text added for clarification, version published in Phys. Rev. Letter

Search for CP violation in the decays D(s)+→KS0π+D^+_{(s)} \to K_S^0\pi^+ and D(s)+→KS0K+D^+_{(s)} \to K_S^0K^+

We have searched for CP violation in the charmed meson decays $D^{+}_{(s)}\to K^0_S\pi^+$ and $D^{+}_{(s)}\to K^0_S K^+$ using 673 fb$^{-1}$ of data collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No evidence for CP violation is observed. We report the most sensitive CP asymmetry measurements to date for these decays: $A_{CP}^{D^+\to K^0_S\pi^+}=(-0.71\pm0.19\pm0.20)$, $A_{CP}^{D^+_s\to K^0_S\pi^+}=(+5.45\pm2.50\pm0.33)$, $A_{CP}^{D^+\to K^0_S K^+}=(-0.16\pm0.58\pm0.25)$, and $A_{CP}^{D^+_s\to K^0_S K^+}=(+0.12\pm0.36\pm0.22)$, where the first uncertainties are statistical and the second are systematic

Measurement of CP violating asymmetries in B^0 -> K^+K^- K^0_S decays with a time-dependent Dalitz approach

We report a measurement of $CP$ violating asymmetries in $B^0(\overline{B}^0) \to K^+ K^- K^0_S$ decays with a time-dependent Dalitz approach. This analysis is based on a data sample of $657\times 10^6$ $B\overline{B}$ pairs accumulated at the $\Upsilon(4S)$ resonance with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. As the result of an unbinned maximum likelihood fit to the selected candidates, the mixing-induced and direct $CP$ violation parameters, $\phi^{\rm eff}_1$ and ${\cal A}_{CP}$ are obtained for $B^0 \to \phi(1020) K^0_S$, $B^0 \to f_0(980) K^0_S$ and other $B^0 \to K^+ K^- K^0_S$ decays. We find four solutions that describe the data. There are \{eqnarray*} \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (32.2 \pm 9.0 \pm 2.6 \pm 1.4)^{\circ}; \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (26.2 \pm 8.8 \pm 2.7 \pm 1.2)^{\circ};\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (27.3 \pm 8.6 \pm 2.8 \pm 1.3)^{\circ}\; {\rm and}\\ \phi_1^{\rm eff}(B^0\to \phi(1020) K^0_S) & = & (24.3 \pm 8.0 \pm 2.9 \pm 5.2)^{\circ}.{eqnarray*}\ The values for the $CP$ violating phase in $B^0\to \phi(1020) K^0_S$ are similar but other properties of the Dalitz plot are quite different for the four solutions. These four solutions have consistent $\phi^{\rm eff}_1$ values for all three $B$ meson decay channels and none of them deviates significantly from the values measured in $B \to (c\bar{c}) K^0$ decays with the currently available statistics. In addition, we find no significant direct $CP$ violation.Comment: submitted to PR

Measurement of e+e−→γχcJe^+e^- \to \gamma\chi_{cJ} via initial state radiation at Belle

The process $e^+e^- \to \gamma\chi_{cJ}$ ($J$=1, 2) is studied via initial state radiation using 980 fb$^{-1}$ of data at and around the $\Upsilon(nS)$ ($n$=1, 2, 3, 4, 5) resonances collected with the Belle detector at the KEKB asymmetric-energy $e^+e^-$ collider. No significant signal is observed except from $\psi(2S)$ decays. Upper limits on the cross sections between $\sqrt{s}=3.80$ and $5.56~{\rm GeV}$ are determined at the 90% credibility level, which range from few pb to a few tens of pb. We also set upper limits on the decay rate of the vector charmonium [$\psi(4040$), $\psi(4160)$, and $\psi(4415)$] and charmoniumlike [$Y(4260)$, $Y(4360)$, and $Y(4660)$] states to $\gamma\chi_{cJ}$.Comment: Accepted by PR

Measurement of the CP-violation Parameter sin2ϕ1\phi_1 with a New Tagging Method at the Υ(5S)\Upsilon(5S) Resonance

We report a measurement of the CP-violation parameter sin2$\phi_1$ at the $\Upsilon(5S)$ resonance using a new tagging method, called "$B$-$\pi$ tagging." In $\Upsilon(5S)$ decays containing a neutral $B$ meson, a charged $B$, and a charged pion, the neutral $B$ is reconstructed in the $J/\psi K_S^0$ CP-eigenstate decay channel. The initial flavor of the neutral $B$ meson at the moment of the $\Upsilon(5S)$ decay is opposite to that of the charged $B$ and may thus be inferred from the charge of the pion without reconstructing the charged $B$. From the asymmetry between $B$-$\pi^+$ and $B$-$\pi^-$ tagged $J/\psi K_S^0$ yields, we determine sin2$\phi_1$ = 0.57 $\pm$ 0.58(stat) $\pm$ 0.06(syst). The results are based on 121 fb$^{-1}$ of data recorded by the Belle detector at the KEKB $e^+ e^-$ collider.Comment: 6 pages, 3 figures (submitted to PRL