1. Measurement of branching fractions for $B \to J/\psi \eta K$ decays and search for a narrow resonance in the $J/\psi \eta$ final stateT. Iwashita, Marko Bračko, Boštjan Golob, Jure Klučar, Samo Korpar, Peter Križan, Rok Pestotnik, Marko Petrič, Marko Starič, Luka Šantelj, Anže Zupanc, 2014, original scientific article Abstract: We report an observation of the $B^{\pm } \to J/\psi \eta K^{\pm }$ and $B^0 \to J/\psi \eta K^0_S$ decays using $772\times 10^{6}B\overline {B}$ pairs collected at the $\Upsilon (4S)$ resonance with the Belle detector at the KEKB asymmetricenergy $e^+e^$ collider. We obtain the branching fractions ${\mathcal B}(B^{\pm }\rightarrow J/\psi \eta K^{\pm })=(1.27\pm 0.11(\hbox {stat.})\pm 0.11(\hbox {syst.}))\times 10^{4}$ and ${\mathcal B}(B^0\to J/\psi \eta K^0_S)=(5.22 \pm 0.78 (\hbox {stat.}) \pm 0.49 (\hbox {syst.}))\times 10^{5}$. We search for a new narrow charmonium(like) state $X$ in the $ J/\psi \eta$ mass spectrum and find no significant excess. We set upper limits on the product of branching fractions, ${\mathcal B}(B^\pm \to XK^\pm){\mathcal B}(X \to J/\psi \eta)$, at $3872\,\hbox {MeV}\,c^{2}$ where a $C$odd partner of $X(3872)$ may exist, at $\psi (4040)$ and $\psi (4160)$ assuming their known mass and width, and over a range from 3.8 to $4.8\,\hbox {GeV}\,c^{2}$. The obtained upper limits at 90% confidence level for $X^{C\hbox {}{\rm odd}}(3872)$, $\psi (4040)$, and $\psi (4160)$ are $3.8\times 10^{6}$, $15.5\times 10^{6}$, and $7.4\times 10^{6}$, respectively. Keywords: C07, C21, particle properties, lepton collider experiments, experimental particle physics Published: 21.07.2017; Views: 545; Downloads: 100 Full text (372,20 KB) This document has many files! More...

2. Highstatistics study of $K^0_S K^0_S$ pair production in twophoton collisionsS. Uehara, Marko Bračko, Boštjan Golob, Jure Klučar, Samo Korpar, Peter Križan, Rok Pestotnik, Marko Petrič, Marko Starič, Luka Šantelj, Anže Zupanc, 2013, original scientific article Abstract: We report a highstatistics measurement of the differential cross section of the process $\gamma \gamma \to K^0_S K^0_S$ in the range $1.05\,{\mathrm {GeV}} \leq W \leq 4.00$ , where W is the centerofmass energy of the colliding photons, using 972 $^{1}$ of data collected with the Belle detector at the KEKB asymmetricenergy e+e− collider operated at and near the $\Upsilon$resonance region. The differential cross section is fitted by parameterized S, $D_0$, $D_2$, $G_0$, and $G_2$wave amplitudes. In the $D_2$ wave, the $f_2$(1270), $a_2$(1320), and $f′_2$(1525) are dominant and a resonance, the $f_2$(2200), is also present. The $f_0$(1710) and possibly the $f_0$(2500) are seen in the S wave. The mass, total width, and product of the twophoton partial decay width and decay branching fraction to the $K \bar {K}$ state $\Gamma _{\gamma \gamma }\mathcal {B}(K \bar {K})$ are extracted for the $f′_2$(1525), $f_0$(1710), $f_2$(2200), and $f_0$(2500). The destructive interference between the $f_2$(1270) and $a_2$(1320) is confirmed by measuring their relative phase. The parameters of the charmonium states $\chi _{c0}$ and $\chi _{c2}$ are updated. Possible contributions from the $\chi _{c0}(2P)$ and $\chi _{c2}(2P)$ states are discussed. A new upper limit for the branching fraction of the P and CPviolating decay channel $\eta _c \to K^0_S K^0_S$ is reported. The detailed behavior of the cross section is updated and compared with QCDbased calculations. Keywords: C00, C05, C07, C21, quantum chromodynamics, quark model, particle properties, lepton collider experiments, experimental particle physics Published: 21.07.2017; Views: 548; Downloads: 56 Full text (2,28 MB) This document has many files! More...

3. First modelindependent Dalitz analysis of $B^0 \to D^0K^{\ast 0}$, $D\to K_S^0\pi ^+\pi ^$ decayK. Negishi, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Tara Nanut, Rok Pestotnik, Marko Petrič, Eva Ribežl, Samo Stanič, Marko Starič, Luka Šantelj, Anže Zupanc, 2016, original scientific article Abstract: We report a measurement of the amplitude ratio $r_S$ of $B^0 \to D^0K^{\ast 0}$ and $B^0 \to \bar {D^0}K^{\ast 0}$ decays with a Dalitz analysis of $D\to K_S^0\pi ^+\pi ^$ decays, for the first time using a modelindependent method. We set an upper limit $r_S < 0.87$ at the 68% confidence level, using the full data sample of $711\,{\rm fb}^{1}$ corresponding to $772\times 10^6$ $B\bar {B}$ pairs collected at the $\Upsilon (4S)$ resonance with the Belle detector at the KEKB $e^+e^$ collider. This result is obtained from observables $x_ = +0.4 ^{+1.0 +0.0}_{0.6 0.1} \pm 0.0$, $y_ = 0.6 ^{+0.8 +0.1}_{1.0 0.0} \pm 0.1$, $x_+ = +0.1 ^{+0.7 +0.0}_{0.4 0.1} \pm 0.1$, and $y_+ = +0.3 ^{+0.5 +0.0}_{0.8 0.1} \pm 0.1$, where $x_\pm = r_S \cos (\delta _S \pm \phi _3)$, $y_\pm = r_S \sin (\delta _S \pm \phi _3)$, and $\phi _3\ (\delta _S)$ is the weak (strong) phase difference between $B^0 \to D^0K^{\ast 0}$ and $B^0 \to \bar {D^0}K^{\ast 0}$. Keywords: CO2, CO3, CabibboKobayashiMaskawa quarkmixing matrix, CP violation, experimental particle physics Published: 21.07.2017; Views: 561; Downloads: 98 Full text (555,01 KB) This document has many files! More...

4. Measurement of D0–D‾0 mixing and search for CP violation in D0 → K+K−,π+π− decays with the full Belle data setMarko Starič, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Tara Nanut, Rok Pestotnik, Marko Petrič, Eva Ribežl, Samo Stanič, Anže Zupanc, 2016, original scientific article Abstract: We report an improved measurement of $D^0–{\overline{D}}^0$ mixing and a search for $CP$ violation in $D^0$ decays to $CP$ even final states $K^+K^−$ and $\pi^+\pi^$. The measurement is based on the final Belle data sample of $976 fb^{−1}$. The results are $y_CP=(1.11±0.22±0.09)%$ and $A_Γ=(−0.03±0.20±0.07)%$, where the first uncertainty is statistical and the second is systematic. Keywords: charm mesons, mixing, CP violation Published: 17.07.2017; Views: 550; Downloads: 270 Full text (577,27 KB) This document has many files! More...

5. Search for B decays to final states with the η c mesonA. Vinokurova, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Rok Pestotnik, Marko Petrič, Eva Ribežl, Samo Stanič, Marko Starič, Luka Šantelj, Anže Zupanc, 2015, original scientific article Abstract: We report a search for B decays to selected final states with the ηc meson: B± → K±ηcπ+π−, B± → K±ηcω, B± → K±ηcη and B± → K±ηcπ0. The analysis is based on 772 × 10^6 B¯B pairs collected at the Υ(4S) resonance with the Belle detector at the KEKB asymmetricenergy e+e− collider. We set 90% confidence level upper limits on the branching fractions of the studied B decay modes, independent of intermediate resonances, in the range (0.6–5.3)×10^−4. We also search for molecularstate candidates in the D^0 ¯D^∗0 − ¯D^0D^∗0, D^0 ¯D^0 + ¯D^0D^0 and D^∗0¯D^∗0 + ¯D^∗0D^∗0 combinations, neutral partners of the Z(3900)± and Z(4020)±, and a poorly understood state X(3915) as possible intermediate states in the decay chain, and set 90% confidence level upper limits on the product of branching fractions to the mentioned intermediate states and decay branching fractions of these states in the range (0.6–6.9)×10^−5. Keywords: exotics, quarkonium, e+e experiments, B physics, particle and resonance production Published: 27.06.2017; Views: 607; Downloads: 347 Full text (129,32 KB) This document has many files! More...

6. Measurement of timedependent CP violation in B 0 → η′K 0 decaysLuka Šantelj, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Tara Nanut, Rok Pestotnik, Marko Petrič, Eva Ribežl, Marko Starič, Anže Zupanc, 2014, original scientific article Abstract: We present a measurement of the timedependent CP violation parameters in B0 → η′K0 decays. The measurement is based on the full data sample containing 772 × 10^6 BB pairs collected at the Υ(4S) resonance using the Belle detector at the KEKB asymmetricenergy e+e− collider. The measured values of the mixinginduced and direct CP violation parameters are:
sin 2ϕ1eff=+0.68±0.07±0.03,
Aη′K0=+0.03±0.05±0.04,
where the first uncertainty is statistical and the second is systematic. The values obtained are the most accurate to date. Furthermore, these results are consistent with our previous measurements and with the worldaverage value of sin 2ϕ1 measured in B0 → J/ψK0 decays. Keywords: CP violation, CKM angle beta, e+e Experiments, B physics Published: 27.06.2017; Views: 583; Downloads: 277 Full text (448,79 KB) This document has many files! More...

7. The physics of the B factoriesAdrian Bevan, Boštjan Golob, Peter Križan, Jure Zupan, Anže Zupanc, Marko Starič, Urban Bitenc, Ilija Bizjak, Marko Bračko, Saša Fratina, Andrej Gorišek, Jure Klučar, Samo Korpar, Rok Pestotnik, Marko Petrič, Luka Šantelj, Peter Smerkol, Samo Stanič, Tomi Živko, Dejan Žontar, 2015, scientific monograph Keywords: experimental particle physics, elementary particles, B mesons, B factories Published: 26.06.2017; Views: 636; Downloads: 206 Full text (31,86 MB) This document has many files! More...

8. 