Opposite-side flavour tagging of B mesons at the LHCb experiment

The calibration and performance of the oppositeside flavour tagging algorithms used for the measurements of time-dependent asymmetries at the LHCb experiment are described. The algorithms have been developed using simulated events and optimized and calibrated with B + →J/ψK +, B0 →J/ψK ∗0 and B0 →D ∗− μ + νμ decay modes with 0.37 fb−1 of data collected in pp collisions at √ s = 7 TeV during the 2011 physics run. The oppositeside tagging power is determined in the B + → J/ψK + channel to be (2.10 ± 0.08 ± 0.24) %, where the first uncertainty is statistical and the second is systematic

Determination of the X(3872) meson quantum numbers

The quantum numbers of the X(3872) meson are determined to be JPC=1++ based on angular correlations in B+→X(3872)K+ decays, where X(3872)→π+π-J/ψ and J/ψ→μ+μ-. The data correspond to 1.0  fb-1 of pp collisions collected by the LHCb detector. The only alternative assignment allowed by previous measurements JPC=2-+ is rejected with a confidence level equivalent to more than 8 Gaussian standard deviations using a likelihood-ratio test in the full angular phase space. This result favors exotic explanations of the X(3872) stat

Rectal cancer management during the COVID-19 pandemic (ReCaP): multicentre prospective observational study.

Concerns over unacceptable high mortality in patients with rectal cancer undergoing surgery or systemic therapy who contract COVID-19 have led to widespread adoption of alternative treatment strategies.The ReCaP study aimed to study these variations and associated outcomes

Measurement of V 0 production ratios in pp collisions at s=0.9 \sqrt {s} = 0.9 and 7 TeV

The $\bar{\Lambda} / \Lambda$ and $\bar{\Lambda} / K^0_\mathrm{S}$ production ratios are measured by the LHCb detector from $0.3\,\mathrm{nb}^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$\,TeV and $1.8\,\mathrm{nb}^{-1}$ at $\sqrt{s} = 7$\,TeV. Both ratios are presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, in the ranges {$0.15 < p_\mathrm{T} < 2.50\,\mathrm{GeV}/c$} and {$2.0<y<4.5$}. Results at the two energies are in good agreement as a function of rapidity loss, $\Delta y = y_\mathrm{beam} - y$, and are consistent with previous measurements. The ratio $\bar{\Lambda} / \Lambda$, measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio $\bar{\Lambda} / K^0_\mathrm{S}$, measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected.The $\bar{\Lambda} / \Lambda$ and $\bar{\Lambda} / K^0_\mathrm{S}$ production ratios are measured by the LHCb detector from $0.3\,\mathrm{nb}^{-1}$ of $pp$ collisions delivered by the LHC at $\sqrt{s} = 0.9$\,TeV and $1.8\,\mathrm{nb}^{-1}$ at $\sqrt{s} = 7$\,TeV. Both ratios are presented as a function of transverse momentum, $p_\mathrm{T}$, and rapidity, $y$, in the ranges {$0.15 < p_\mathrm{T} < 2.50\,\mathrm{GeV}/c$} and {$2.0<y<4.5$}. Results at the two energies are in good agreement as a function of rapidity loss, $\Delta y = y_\mathrm{beam} - y$, and are consistent with previous measurements. The ratio $\bar{\Lambda} / \Lambda$, measuring the transport of baryon number from the collision into the detector, is smaller in data than predicted in simulation, particularly at high rapidity. The ratio $\bar{\Lambda} / K^0_\mathrm{S}$, measuring the baryon-to-meson suppression in strange quark hadronisation, is significantly larger than expected

First evidence of direct CP violation in charmless two-body decays of Bs0 mesons

Using a data sample corresponding to an integrated luminosity of 0.35 fb(-1) collected by LHCb in 2011, we report the first evidence of CP violation in the decays of B-s(0) mesons to K-+/-pi(-/+)pairs, A(CP)(B-s(0) -> K pi) = 0.27 +/- 0.08(stat) +/- 0.02(syst), with a significance of 3.3 sigma. Furthermore, we report the most precise measurement of CP violation in the decays of B-0 mesons to K-+/-pi(-/+) pairs, A(CP)(B-0 -> K pi) = -0.088 +/- 0.011(stat) +/- 0.008(syst), with a significance exceeding 6 sigma. RI Galli, Domenico/A-1606-2012; Coca, Cornelia/B-6015-2012; Petrolini, Alessandro/H-3782-2011; Sarti, Alessio/I-2833-2012; Carbone, Angelo/C-8289-2012; manca, giulia/I-9264-2012; de Paula, Leandro/I-9278-2012; Patrignani, Claudia/C-5223-2009; Marconi, Umberto/J-2263-2012; de Simone, Patrizia/J-3549-2012; Cardini, Alessandro/J-5736-2012; Teodorescu, Eliza/K-3044-201

Rectal cancer management during the COVID-19 pandemic (ReCaP): multicentre prospective observational study

Concerns over unacceptable high mortality in patients with rectal cancer undergoing surgery or systemic therapy who contract COVID-19 have led to widespread adoption of alternative treatment strategies.The ReCaP study aimed to study these variations and associated outcomes

Formation of a conceptual framework during the development of a patient-reported outcome measure for early gastrointestinal recovery: phase I of the PRO-diGi study

Aim Patients admitted to hospital for abdominal surgery often experience gastrointestinal dysfunction. Many studies have reported outcomes following gastrointestinal dysfunction, yet there is no unified definition of recovery or a validated patient-reported outcome measure (PROM). The first stage of PROM development requires formation of a conceptual framework to identify key themes to patients. The aim of this study was to utilize semistructured interviews to identify core themes and concepts relevant to patients to facilitate development of a conceptual framework. Method Adult patients admitted to hospital for major gastrointestinal, urological or gynaecological surgery, in an emergency or elective setting, were eligible to participate. Patients treated nonoperatively for small bowel obstruction were also eligible. Interviews were conducted by telephone, audio-recorded, transcribed, coded and analysed using NVivo software by two researchers and reviewed by lay members of the steering group. Interviews continued until data saturation was reached. Ethical approval was gained prior to interviews (21/WA/0231). Results Twenty nine interviews were completed (17 men, median age 64 years) across three specialties (20 gastrointestinal, six gynaecological, three urological). Two overarching themes of ‘general recovery’ and ‘gastrointestinal symptoms’ were identified. General recovery included three themes: ‘life impact’, ‘mental impact’, including anxiety, and ‘physical impact’, including fatigue. Gastrointestinal symptoms included three themes: ‘abdominal symptoms’ such as pain, ‘diet and appetite’ and ‘expulsory function’, such as stool frequency. A total of 18 gastrointestinal symptoms were identified during patient recovery—many of which lasted several weeks following discharge. Conclusion This study reports a range of gastrointestinal and nongastrointestinal symptoms experienced by patients during early gastrointestinal recovery. Identified symptoms have been synthesized into a conceptual framework to enable development of a definitive PROM for early gastrointestinal recovery

Legacy of COVID‐19 – the opportunity to enhance surgical services for patients with colorectal disease

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Laparoscopic versus open colorectal surgery in the acute setting (LaCeS trial): a multicentre randomized feasibility trial

AbstractBackgroundApproximately 30,000 people per annum undergo major, emergency abdominal, gastrointestinal surgery, of which 36% (~10,800) are carried out for emergency colorectal pathology. Approximately 14% of all patients requiring emergency surgery undergo laparoscopic surgery. AimsThe aims of the LaCeS feasibility trial (Laparoscopic versus Open Colorectal Surgery in the Acute Setting) were to assess the feasibility, safety and acceptability of performing a large-scale definitive phase III randomised controlled trial with a comparison of emergency laparoscopic with open surgery for acute colorectal pathology. MethodsLaCeS was designed as a prospective, multicentre, single blind, parallel group, pragmatic, randomised controlled feasibility trial with an integrated qualitative study. Randomisation was performed centrally with patients being randomised on a 1:1 basis between laparoscopic or open surgery. ResultsA total of 64 patients were recruited across 5 centres. The overall average steady state recruitment rate was 1.2 patients/month. Baseline compliance for clinical and HrQoL data was 99.8% and 93.8% respectively. The conversion rate from laparoscopic to open surgery was 39.4% (95% CI 22.9% – 57.9%). The 30 day post-operative complication rate was 27.3% (95% CI 13.3- 45.5) in the laparoscopic arm and 41.9% (95% CI 24.6 – 60.9) in the open arm. DiscussionThe LaCeS feasibility trial has demonstrated that it is possible to evaluate laparoscopic surgery in the emergency colorectal setting within the context of a randomised controlled trial. LaCeS has demonstrated that it is possible to recruit to a surgical trial in the emergency setting, with good compliance to trial procedures and processes, and overall acceptability by patients and clinicians. The safety data obtained for laparoscopic emergency colorectal surgery indicate an acceptable safety profile, particularly when considering it to that observed in the open arm.Trial Registration ISRCTN15681041 https://doi.org/10.1186/ISRCTN15681041.Funding body: National Institute of Health Research – Research for Patient Benefi