1. Search for tetraquark states ▫$X_{c c \bar{s} \bar{s}}$▫ in ▫$D_s^+ D_s^+$▫ (▫$D_s^{\ast +} D_s^{\ast +}$▫) final states at BelleX. Y. Gao, Jyotirmoi Borah, Marko Bračko, Samo Korpar, Peter Križan, Rok Pestotnik, Tomaž Podobnik, Samo Stanič, Marko Starič, Luka Šantelj, Valentina Zhukova, 2022, original scientific article Abstract: A search for double-heavy tetraquark state candidates Xccs¯s¯ decaying to Dþ s Dþ s and Dþ s Dþ s is presented for the first time using the data samples of 102 × 106 ϒð1SÞ and 158 × 106 ϒð2SÞ events, and the data samples at ffiffi ps ¼ 10.52, 10.58, and 10.867 GeV corresponding to integrated luminosities of 89.5, 711.0, and 121.4 fb−1, respectively, accumulated with the Belle detector at the KEKB asymmetric energy electron-positron collider. The invariant-mass spectra of the Dþ s Dþ s and Dþ s Dþ s are studied to search for possible resonances. No significant signals are observed, and the 90% confidence level upper limits on the product branching fractions [Bðϒð1S; 2SÞ → Xccs¯s¯ þ anythingÞ × BðXccs¯s¯ → Dþ s Dþ s ðDþ s Dþ s ÞÞ] in ϒð1S; 2SÞ inclusive decays and the product values of Born cross section and branching fraction [σðeþe− → Xccs¯s¯ þ anythingÞ × BðXccs¯s¯ → Dþ s Dþ s ðDþ s Dþ s ÞÞ] in eþe− collisions at pffiffis ¼ 10.52, 10.58, and 10.867 GeV under different assumptions of Xccs¯s¯ masses and widths are obtained.
Keywords: tetraquark states, final states at Belle
Published in DKUM: 15.04.2025; Views: 0; Downloads: 3
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2. Slow control of the Belle II Aerogel Ring Imaging detectorRok Pestotnik, Karol Adamczyk, Rok Dolenec, Samo Korpar, Peter Križan, Andrej Lozar, Luka Šantelj, Andrej Seljak, Luka Senekovič, 2023, original scientific article Published in DKUM: 09.05.2024; Views: 145; Downloads: 21
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3. Exploring the potential of a Cherenkov TOF PET scanner : a simulation studyGašper Razdevšek, Rok Pestotnik, Peter Križan, Samo Korpar, Dania Consuegra Rodríguez, Andrej Seljak, Andrej Studen, Rok Dolenec, 2023, original scientific article Abstract: The detection of annihilation photons in positron emission tomography (PET) is based on scintillation light detection, but an interesting alternative is detection based on Cherenkov photons. Dense Cherenkov radiators provide an opportunity for high gamma detection efficiency—due to their high stopping power and photofraction—and excellent coincidence time resolution (CTR). However, because only a few tens of Cherenkov photons follow a gamma interaction in the radiator, the detection efficiency, and the energy resolution of a pure Cherenkov detector are an issue. This work explores gamma detection efficiency and CTR of PbF2-based detectors with different surface treatments and photodetectors covering one, two, or all crystal faces. Following the detector simulation analysis, we investigate the potential performance of a full-size Cherenkov PET scanner and quantitatively compare image quality with a commercial clinical PET scanner. We demonstrate that even though pure Cherenkov scanners have basically no energy resolution, the scatter fraction of around 50% is not prohibitively large, and images comparable to the state-of-the-art clinical PET scanner can be achieved due to improved efficiency and CTR attainable with PbF2.
Keywords: Cherenkov TOF PET Scanner
Published in DKUM: 02.04.2024; Views: 218; Downloads: 12
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4. LAPPD operation using ToFPETv2 PETSYS ASICAndrej Seljak, Marko Bračko, Rok Dolenec, Peter Križan, Andrej Lozar, Rok Pestotnik, Samo Korpar, 2023, published scientific conference contribution Abstract: Single photon sensitive detectors used in high energy physics are, in some applica-tions, required to cover areas the size of several m2, 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 second 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. 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.
Keywords: data acquisition circuits, data acquisition concept, front-end electronics for detector readou, digital electronic circuits
Published in DKUM: 06.02.2024; Views: 278; Downloads: 25
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5. Analiza avtomatizacije poslovnih procesov z microsoft power platformŽan Korpar, 2023, master's thesis Abstract: Microsoft Power Platform je platforma, ki omogoča digitalizacijo in avtomatizacijo poslovnih procesov. Digitalizacija med drugimi poveča učinkovitost podjetja in izboljša interakcijo s strankami, avtomatizacija pa zmanjša možnost človeških napak in stroške. Ključne komponente platforme so Power BI, Power Automate in Dynamics 365. V sklopu magistrskega dela smo analizirali vzpostavljen sistem v izbranem podjetju. S pomočjo KPI-jev smo primerjali poslovanje pred in po uvedbi le-tega. Uvedba Power Platform je v podjetju izboljšala nadzor nad uporabniki, povečala število aktivnosti in avtomatsko obnovljenih pogodb, ter izboljšala odzivni čas podpore strankam. Power Platform lahko torej izboljša učinkovitost podjetja in s tem konkurenčnost na trgu.
Keywords: Microsoft Power Platform, poslovni procesi, avtomatizacija, BPMN, življenjski cikel procesov
Published in DKUM: 03.11.2023; Views: 337; Downloads: 56
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6. Search for ▫$Z^\prime \to \mu^+ \mu^-$▫ in the ▫$L_\mu - L_\tau$▫ gauge-symmetric model at BelleT. Czank, Karol Adamczyk, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Manca Mrvar, Rok Pestotnik, Tomaž Podobnik, Samo Stanič, Marko Starič, Luka Šantelj, 2022, original scientific article Abstract: We search for a new gauge boson Z′ that couples only to heavy leptons and their corresponding neutrinos in the process e+e−→Z′(→μ+μ−)μ+μ−, using a 643 fb−1 data sample collected by the Belle experiment at or near the Υ(1S,2S,3S,4S,5S) resonances at the KEKB collider. While previous searches for Z′ performed a data-based estimation of the initial state radiation effect, our search for the Z′ is the first to include effects due to initial state radiation in the signal simulated samples that were used in estimating the detection efficiency. No signal is observed in the Z′ mass range of 0.212–10 GeV/c2, and we set an upper limit on the coupling strength, g′, constraining the possible Z′ contribution to the anomalous magnetic dipole moment of the muon.
Keywords: Extensions of gauge sector, leptonic, semileptonic & radiative decays
Published in DKUM: 25.09.2023; Views: 455; Downloads: 39
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7. Measurement of two-particle correlations of hadrons in ▫$e^+ e^-$▫ collisions at BelleY.-C. Chen, Marko Bračko, Samo Korpar, Peter Križan, Tomaž Podobnik, Marko Starič, Luka Šantelj, 2022, original scientific article Abstract: The measurement of two-particle angular correlation functions in high-multiplicity e+e− collisions at √s=10.52 GeV is reported. In this study, the 89.5 fb−1 of hadronic e+e− annihilation data collected by the Belle detector at KEKB are used. Two-particle angular correlation functions are measured in the full relative azimuthal angle (Δϕ) and three units of pseudorapidity (Δη), defined by either the electron beam axis or the event-shape thrust axis, and are studied as a function of charged-particle multiplicity. The measurement in the thrust axis analysis, with mostly outgoing quark pairs determining the reference axis, is sensitive to the region of additional soft gluon emissions. No significant anisotropic collective behavior is observed with either coordinate analyses. Near-side jet correlations appear to be absent in the thrust axis analysis. The measurements are compared to predictions from various event generators and are expected to provide new constraints to the phenomenological models in the low-energy regime.
Keywords: Particle & resonance production, Quark & gluon jets, Quark-gluon plasma
Published in DKUM: 24.08.2023; Views: 396; Downloads: 9
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8. Measurement of the branching fraction and ▫$CP$▫ asymmetry for ▫$B \to \bar{D}^0 \pi$▫ decaysT. Bloomfield, Jyoti Prakash Biswal, Marko Bračko, Samo Korpar, Peter Križan, Rok Pestotnik, Tomaž Podobnik, Marko Starič, Luka Šantelj, 2022, original scientific article Abstract: We measure the branching fractions and CP asymmetries for the decays B⁰ → D¯ 0π⁰ and B⁺ → D¯ 0π⁺, using a data sample of 772 × 10⁶ BB¯ pairs collected at the ϒ(4S) resonance with the Belle detector at the KEKB e⁺e− collider. The branching fractions obtained and direct CP asym-metries are B(B⁰ → D¯ 0π⁰)=[2.70 0.06(stat) 0.10(syst)]×10−⁴, B(B⁺ → D¯ 0π⁺)=[4.53 0.02(stat) 0.15(syst)]×10−³, ACP(B⁰ → D¯ 0π⁰)= [+0.42 2.05(stat) 1.22(syst)]%, and ACP(B⁺ → D¯ 0π⁺) = [+0.19 0.36(stat) 0.57(syst)]%. The measurements of B are the most precise to date and are in good agreement with previous results, as is the measurement of ACP(B⁺ → D¯ 0π⁺). The measurement of ACP for B⁰ → D¯ 0π⁰ is the first for this mode, and the value is consistent with Standard Model expectations.
Keywords: branching fraction, hadronic decays, particle decays, mesons, CP violation, precision measurements
Published in DKUM: 17.08.2023; Views: 364; Downloads: 39
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9. Search for the decay ▫$B_s^0 \to \eta \eta$▫S. Bhuyan, Jyoti Prakash Biswal, Marko Bračko, Boštjan Golob, Samo Korpar, Peter Križan, Rok Pestotnik, Marko Starič, Luka Šantelj, 2022, original scientific article Abstract: We report results from a search for the decay B0s→ηη using 121.4 fb−1 of data collected at the Υ(5S) resonance with the Belle detector at the KEKB asymmetric-energy e+e− collider. We do not observe any signal and set an upper limit on the branching fraction of 14.3×10−5 at 90% confidence level. This result represents a significant improvement over the previous most stringent limit.
Published in DKUM: 17.08.2023; Views: 270; Downloads: 33
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10. Učinki oglaševanja na družabnih omrežjih v športnih klubih: analiza primeraŽiga Korpar, 2022, undergraduate thesis Abstract: Dandanes več kot polovica svetovnega prebivalstva uporablja družabna omrežja, ta številka se bo z leti le še povečevala. To nam pove, kako pomembna so družabna omrežja v našem življenju. Za oglaševalce to pomeni veliko priložnost, predvsem zaradi podrobnega ciljanja svojih ciljnih skupin, to pa izloči nepotrebno potrošnjo za skupine ljudi, ki jih izdelek ali storitev ne zanima. Družabna omrežja prav tako ponujajo možnost enostavnega pregleda v statistiko oglasov, katera je težko dosegljiva pri tradicionalnih metodah oglaševanja.
V prvem delu diplomskega dela smo najprej opredelili oglaševanje, pojasnili kako deluje in zakaj je pomembno. Predstavili smo tradicionalno kot tudi digitalno oglaševanje in njune slabosti oziroma prednosti ter različne vrste oglaševanja. Poglavje smo zaključili s primerjavo tradicionalnega in digitalnega oglaševanja. Nato smo se lotili družabnih omrežij, kjer smo pojasnili kaj so, njihovo zgodovino in različne tipe. Pojasnili smo kako delujejo družabna omrežja ter prikazali skupne dele vsem omrežjem. Analizirali smo njihove prednosti in slabosti ter z grafom prikazali priljubljena družabna omrežja, nekaj od njih smo jih tudi opisali. Na koncu poglavja smo se lotili analize raziskave o uporabnosti družabnih omrežij v Sloveniji.
V drugem delu smo najprej predstavili športni klub, katerega oglase smo na koncu diplomskega dela analizirali. Postavili smo se v vlogo oglaševalca in objavili oglase na Facebooku in Instagramu. Ugotovili smo, da se v času objavljenega oglasa zelo poveča obisk spletnih strani družabnih omrežij, prav tako se poveča število prejetih sporočil strank, z interesom pričetka treniranja.
Keywords: družabna omrežja, oglaševanje, športni klub, Facebook, Instagram.
Published in DKUM: 17.10.2022; Views: 523; Downloads: 66
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