Semileptonic Hyperon Decays at LHCb Brea Rodríguez, A
Journal of physics. Conference series,
04/2020, Letnik:
1526, Številka:
1
Journal Article
Recenzirano
Odprti dostop
Semileptonic Hyperon Decays (SHD) allow to test Beyond the Standard Model physics with operators not accessible to kaon decays. In this document we will discuss the prospects of the LHCb experiment ...to improve the existing measurement of muonic SHD. A background rejection study has been made using the LHCb simulation in order to investigate the power to distinguish between the Λ0→pμ−ν¯ decay and its main background, the Λ0 → pπ− decay. Two variables were explored, and their rejection power was estimated by applying a selection criteria. In addition, the estimated Λ0→pμ−ν¯ yield at LHCb was calculated.
A
bstract
This report details the capabilities of LHCb and its upgrades towards the study of kaons and hyperons. The analyses performed so far are reviewed, elaborating on the prospects for some key ...decay channels, while proposing some new measurements in LHCb to expand its strangeness research program.
In this paper, we describe the potential of the LHCb experiment to detect stealth physics. This refers to dynamics beyond the standard model that would elude searches that focus on energetic objects ...or precision measurements of known processes. Stealth signatures include long-lived particles and light resonances that are produced very rarely or together with overwhelming backgrounds. We will discuss why LHCb is equipped to discover this kind of physics at the Large Hadron Collider and provide examples of well-motivated theoretical models that can be probed with great detail at the experiment.
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•First demonstration of LIPSS as polarization gratings.•Optical behavior can be modified changing LIPSS morphology in the fabrication process.•Results supported by computational ...modelling of light-LIPSS interaction.•Fast LIPSS generation with a setup based on line-focused beam and imaging system.•Potential applications as reflective waveplates, using a simple, one-step process.
A fast and reliable method for the fabrication of polarization modifying devices using femtosecond laser is reported. A setup based on line focusing is used for the generation of LIPSS on stainless steel, processing at different speeds between 0.8 and 2.4 mm/s with constant energy per pulse of 1.4 mJ. SEM and AFM characterizations of the LIPSS show a progressive increase in period as the processing speed increases, while height remains approximately constant in the studied range. Optical characterization of the devices shows an induced change in the polarization of the reflected beam that varies with the processing speed, which allows a controlled fabrication of these devices.
We describe a fully GPU-based implementation of the first level trigger for the upgrade of the LHCb detector, due to start data taking in 2021. We demonstrate that our implementation, named Allen, ...can process the 40 Tbit/s data rate of the upgraded LHCb detector and perform a wide variety of pattern recognition tasks. These include finding the trajectories of charged particles, finding proton–proton collision points, identifying particles as hadrons or muons, and finding the displaced decay vertices of long-lived particles. We further demonstrate that Allen can be implemented in around 500 scientific or consumer GPU cards, that it is not I/O bound, and can be operated at the full LHC collision rate of 30 MHz. Allen is the first complete high-throughput GPU trigger proposed for a HEP experiment.
Develop a silk fibroin (SF)-based artificial endothelial graft for its use in a rabbit Descemet membrane endothelial keratoplasty (DMEK).
Human and rabbit artificial corneal endothelial grafts were ...developed through the culture of human and rabbit corneal endothelial cells (CECs) on SF films. Rabbit artificial SF endothelial grafts were transplanted in a DMEK surgery into a rabbit in vivo model.
SF artificial endothelial grafts showed the characteristic endothelial markers: zonula occludens (ZO-1) and Na+/K+ ATPase. In a rabbit model of DMEK surgery, SF artificial endothelial graft restored the corneal transparency and thickness at 6 week of follow-up. Anterior segment optical coherence tomography revealed the SF graft as a fully integrated component in the corneal tissue, displaying a similar corneal thickness and endothelial cell count when compared with its healthy contralateral cornea. Histologic analysis showed that the SF artificial endothelial graft was attached and integrated on the surface of the corneal stroma without a significant inflammatory reaction, and rabbit CECs consisted in a monolayer that showed their characteristic markers ZO-1 and Na+/K+ ATPase, suggesting proper intercellular junctions and cellular pump function.
We have developed SF films with biological properties that supported the growth of rabbit and human CECs, which showed normal morphology and characteristic markers; and with mechanical properties that allowed its use in a DMEK surgery, proving its in vivo functionality in a rabbit model of endothelial dysfunction.
Patients with metastatic renal carcinoma (mRCC) treated with first-line pazopanib were not included in the International Metastatic Renal Cell Carcinoma Database Consortium (IMDC) prognostic model. ...SPAZO (NCT02282579) was a nation-wide retrospective observational study designed to assess the effectiveness and validate the IMDC prognostic model in patients treated with first-line pazopanib in clinical practice.
Data of 278 patients, treated with first-line pazopanib for mRCC in 34 centres in Spain, were locally recorded and externally validated. Mean age was 66 years, there were 68.3% male, 93.5% clear-cell type, 74.8% nephrectomized, and 81.3% had ECOG 0-1. Metastatic sites were: lung 70.9%, lymph node 43.9%, bone 26.3%, soft tissue/skin 20.1%, liver 15.1%, CNS 7.2%, adrenal gland 6.5%, pleura/peritoneum 5.8%, pancreas 5%, and kidney 2.2%. After median follow-up of 23 months, 76.4% had discontinued pazopanib (57.2% due to progression), 47.9% had received second-line targeted therapy, and 48.9% had died.
According to IMDC prognostic model, 19.4% had favourable risk (FR), 57.2% intermediate risk (IR), and 23.4% poor risk (PR). No unexpected toxicities were recorded. Response rate was 30.3% (FR: 44%, IR: 30% PR: 17.3%). Median progression-free survival (whole population) was 11 months (32 in FR, 11 in IR, 4 in PR). Median and 2-year overall survival (whole population) were 22 months and 48.1%, respectively (FR: not reached and 81.6%, IR: 22 and 48.7%, PR: 7 and 18.8%). These estimations and their 95% confidence intervals are fully consistent with the outcomes predicted by the IMDC prognostic model.
Our results validate the IMDC model for first-line pazopanib in mRCC and confirm the effectiveness and safety of this treatment.
A narrow pentaquark state, Pc(4312)+, decaying to J/ψp, is discovered with a statistical significance of 7.3σ in a data sample of Λb0→J/ψpK− decays, which is an order of magnitude larger than that ...previously analyzed by the LHCb Collaboration. The Pc(4450)+ pentaquark structure formerly reported by LHCb is confirmed and observed to consist of two narrow overlapping peaks, Pc(4440)+ and Pc(4457)+, where the statistical significance of this two-peak interpretation is 5.4σ. The proximity of the Σc+D¯0 and Σc+D¯*0 thresholds to the observed narrow peaks suggests that they play an important role in the dynamics of these states.
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