The most precise measurements to date of the $^{3}_{Λ}$H lifetime τ and Λ separation energy BΛ are obtained using the data sample of Pb–Pb collisions at $\sqrt{s_{NN}}$ = 5.02 TeV collected by ALICE ...at the LHC. The $^{3}_{Λ}$H is reconstructed via its charged two-body mesonic decay channel ($^{3}_{Λ}$H → 3He + π– and the charge-conjugate process). The measured values τ = 253 ± 11 (stat.) ± 6(syst.) ps and BΛ = 102 ± 63 (stat.) ± 67 (syst.) keV are compatible with predictions from effective field theories and confirm that the $^{3}_{Λ}$H structure is consistent with a weakly-bound system.
The ALICE Collaboration reports three measurements in ultraperipheral proton-lead collisions at forward rapidity. The exclusive two-photon process γγ → μ+μ- and the exclusive photoproduction of J/ψ ...are studied. J/ψ photoproduction with proton dissociation is measured for the first time at a hadron collider. The cross section for the two-photon process of dimuons in the invariant mass range from 1 to 2.5 GeV/c2 agrees with leading-order quantum electrodynamics calculations. The exclusive and dissociative cross sections for J/ψ photoproductions are measured for photon-proton center-of-mass energies from 27 to 57 GeV. They are in good agreement with HERA results.
The pseudorapidity density of charged particles with minimum transverse momentum (pT) thresholds of 0.15, 0.5, 1, and 2 GeV/c is measured in pp collisions at the center of mass energies of $\sqrt{s}$ ...= 5.02 and 13 TeV with the ALICE detector. The study is carried out for inelastic collisions with at least one primary charged particle having a pseudorapidity (η) within ± 0.8 and pT larger than the corresponding threshold. In addition, measurements without pT-thresholds are performed for inelastic and nonsingle-diffractive events as well as for inelastic events with at least one charged particle having |η| < 1 in pp collisions at $\sqrt{s}$ = 5.02 TeV for the first time at the LHC. These measurements are compared to the pythia 6, pythia 8, and epos-lhc models. In general, the models describe the η dependence of particle production well. However, discrepancies are observed for the highest transverse momentum threshold (pT > 2 GeV/c), highlighting the importance of such measurements for tuning event generators. The new measurements agree within uncertainties with results from the ATLAS and CMS experiments obtained at $\sqrt{s}$ =13 TeV .
Measurement of the Λ hyperon lifetime Alizadehvandchali, N.; Alkin, A.; Alocco, G. ...
Physical review. D,
08/2023, Letnik:
108, Številka:
3
Journal Article
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A new, more precise measurement of the Λ hyperon lifetime is performed using a large data sample of Pb-Pb collisions at $\sqrt{s_{NN}}$=5.02 TeV with ALICE. The Λ and $\bar{Λ}$ hyperons are ...reconstructed at midrapidity using their two-body weak decay channel Λ→p+π- and $\bar{Λ}$→$\bar{p}$+π+. The measured value of the Λ lifetime is τΛ=261.07±0.37(stat.)±0.72(syst.) ps. The relative difference between the lifetime of Λ and $\bar{Λ}$, which represents an important test of CPT invariance in the strangeness sector, is also measured. The obtained value (τΛ-τ$\bar{Λ}$)/τΛ=0.0013±0.0028(stat.)±0.0021(syst.) is consistent with zero within the uncertainties. Both measurements of the Λ hyperon lifetime and of the relative difference between τΛ and τ$\bar{Λ}$ are in agreement with the corresponding world averages of the Particle Data Group and about a factor of three more precise.
Moisture absorption is a water diffusion process known to alter many of the mechanical properties of polymer-based composites. This study presents ultrasonic characterization of moisture content ...based on the transmission of acoustic waves through composite plates. The elastic constants of fourteen plates with different controlled water contents are obtained. First the redundancy of the results allows to validate the characterization process and the assumption made on the samples' symmetry. The sensitivity of the process to moisture content is then discussed
This is an addendum to the article JHEP 11 (2015) 205 1 . The figures 3 (right), 4 (right) and 5 are updated with published results on non-prompt J/ψ-meson production from the CMS collaboration 2 . ...Figure not available: see fulltext.
Abstract The transverse momentum (p T) dependence of the nuclear modification factor R AA and the centrality dependence of the average transverse momentum p T for inclusive J/psi have been measured ...with ALICE for Pb-Pb collisions at ... TeV in the e+e- decay channel at mid-rapidity (|y| < 0.8). The p T is significantly smaller than the one observed for pp collisions at the same centre-of-mass energy. Consistently, an increase of R AA is observed towards low p T. These observations might be indicative of a sizable contribution of charm quark coalescence to the J/psi production. Additionally, the fraction of non-prompt J/psi from beauty hadron decays, f B, has been determined in the region 1.5 < p T < 10 GeV/c in three centrality intervals. No significant centrality dependence of f B is observed. Finally, the R AA of non-prompt J/psi is discussed and compared with model predictions. The nuclear modification in the region 4.5 < p T < 10 GeV/c is found to be stronger than predicted by most models. Figure not available: see fulltext.
Diffuse large B-cell lymphoma (DLBCL) is the most frequent lymphoid malignancy affecting adults. The NF-κB transcription factor family is activated by 2 main pathways, the canonical and the ...alternative NF-κB activation pathway, with different functions. The alternative NF-κB pathway leads to activation of the transcriptionally active RelB NF-κB subunit. Alternative NF-κB activation status and its role in DLBCL pathogenesis remain undefined. Here, we reveal a frequent activation of RelB in a large cohort of DLBCL patients and cell lines, independently of their activated B-cell-like or germinal center B-cell-like subtype. RelB activity defines a new subset of patients with DLBCL and a peculiar gene expression profile and mutational pattern. Importantly, RelB activation does not correlate with the MCD genetic subtype, enriched for activated B-cell-like tumors carrying MYD88L265P and CD79B mutations that cooperatively activate canonical NF-κB, thus indicating that current genetic tools to evaluate NF-κB activity in DLBCL do not provide information on the alternative NF-κB activation. Furthermore, the newly defined RelB-positive subgroup of patients with DLBCL exhibits a dismal outcome after immunochemotherapy. Functional studies revealed that RelB confers DLBCL cell resistance to DNA damage-induced apoptosis in response to doxorubicin, a genotoxic agent used in the front-line treatment of DLBCL. We also show that RelB positivity is associated with high expression of cellular inhibitor of apoptosis protein 2 (cIAP2). Altogether, RelB activation can be used to refine the prognostic stratification of DLBCL and may contribute to subvert the therapeutic DNA damage response in a segment of patients with DLBCL.
Flow cytometry (FC) is increasingly recognized as an important tool in the diagnosis and prognosis of myelodysplastic syndromes (MDS). However, validation of current assays and agreement upon the ...techniques are prerequisites for its widespread acceptance and application in clinical practice. Therefore, a working group was initiated (Amsterdam, 2008) to discuss and propose standards for FC in MDS. In 2009 and 2010, representatives from 23, mainly European, institutes participated in the second and third European LeukemiaNet (ELN) MDS workshops. In the present report, minimal requirements to analyze dysplasia are refined. The proposed core markers should enable a categorization of FC results in cytopenic patients as 'normal', 'suggestive of', or 'diagnostic of' MDS. An FC report should include a description of validated FC abnormalities such as aberrant marker expression on myeloid progenitors and, furthermore, dysgranulopoiesis and/or dysmonocytopoiesis, if at least two abnormalities are evidenced. The working group is dedicated to initiate further studies to establish robust diagnostic and prognostic FC panels in MDS. An ultimate goal is to refine and improve diagnosis and prognostic scoring systems. Finally, the working group stresses that FC should be part of an integrated diagnosis rather than a separate technique.
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