3,629 research outputs found

    Constraints on the χ_(c1) versus χ_(c2) polarizations in proton-proton collisions at √s = 8 TeV

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    The polarizations of promptly produced χ_(c1) and χ_(c2) mesons are studied using data collected by the CMS experiment at the LHC, in proton-proton collisions at √s=8  TeV. The χ_c states are reconstructed via their radiative decays χ_c → J/ψγ, with the photons being measured through conversions to e⁺e⁻, which allows the two states to be well resolved. The polarizations are measured in the helicity frame, through the analysis of the χ_(c2) to χ_(c1) yield ratio as a function of the polar or azimuthal angle of the positive muon emitted in the J/ψ → μ⁺μ⁻ decay, in three bins of J/ψ transverse momentum. While no differences are seen between the two states in terms of azimuthal decay angle distributions, they are observed to have significantly different polar anisotropies. The measurement favors a scenario where at least one of the two states is strongly polarized along the helicity quantization axis, in agreement with nonrelativistic quantum chromodynamics predictions. This is the first measurement of significantly polarized quarkonia produced at high transverse momentum

    Immunotherapy-Based Combinations in First-Line Urothelial Cancer: A Systematic Review and Individual Patient Data (IPD) Meta-Analysis

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    Introduction. Platinum-based chemotherapy represents the standard of care (SoC) for the first-line treatment of advanced urothelial carcinoma (mUC). The benefit of adding immune checkpoint inhibitors (ICIs) to platinum-based chemotherapy was recently investigated. We performed an individual patient data (IPD) meta-analysis of phase 3 clinical trials comparing ICI-based treatments. Methods. A systematic literature search was conducted on the MEDLINE and CENTRAL databases. The results were filtered by including only reports on clinical trials or randomized clinical trials from 2018 to 2023, including 3047 patients from four clinical trials (EV302, CHECKMATE-901, IMVIGOR130, KEYNOTE-361). An IPD meta-analysis was performed by reconstructing IPD from Kaplan-Meier curves. The primary endpoints were overall survival (OS) and progression-free survival (PFS) of Pembrolizumab + EV compared to experimental arms of the other trials of immunotherapy + chemotherapy. Results. The OS analysis showed an advantage of IPD from EV302 vs. all the other trials. For EV302 vs. KEYNOTE-361, the HR was 0.51; for EV302 vs. IMVIGOR130, the HR was 0.47; and for EV302 vs. CHECKMATE-901, the HR was 0.66 (CI 95% 0.51-0.85). In the PFS analysis, the EV302 arm showed a statistically significant advantage compared to CHECKMATE-901 (HR 0.66) and versus IMVIGOR130 (HR 0.51). Limitations: By using reconstructed IPD curves, it was not possible to adjust patient-level covariates, and the heterogeneity of the included population may have affected the pooled results. Conclusions: The EV302 experimental arm showed better OS and PFS when compared to the other immunochemotherapy combinations. An immunochemotherapy combination strategy at the beginning of treatment in mUC seems to be superior in terms of OS and PFS compared to platinum-based chemotherapy alone. EV-Pembrolizumab resulted to have better outcomes compared to avelumab, rather than other immunochemotherapy combinations. However, given the heterogeneity of these studies, a longer follow up and prospective trials are needed to confirm these data
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