MULTI-PURPOSE ROLL MILL STAND

FIELD: process engineering. SUBSTANCE: invention relates to metallurgy, namely to rolling and can be used to produce rails and H-sections. Proposed mill stand comprises two horizontal rollers, two vertical rollers fitted in C-like pads and mechanisms to move said rollers along and across rolling direction. Every horizontal roller is arranged in cartridge fitted in C-like pad fixed in lengthwise direction and can move along or across rolling direction. Note here that cartridge width in lengthwise direction is smaller than respective width pad by vertical roller axis travel. EFFECT: displacement of vertical roller axes relative to plane of horizontal roller axes and displacement of vertical roller along or across rolling direction. 4 dwg.Изобретение относится к сортовой прокатке и может быть использовано при производстве рельсов и двутавровых профилей. Универсальная прокатная клеть содержит два горизонтальных валка с подушками, два вертикальных валка, установленных в С-образных подушках, и механизмы перемещения валков вдоль и поперек прокатки. Каждый вертикальный валок размещен в кассете, установленной в неподвижной в продольном направлении С-образной подушке, и может перемещаться в ней по направлению или против направления прокатки, причем ширина кассеты в продольном направлении меньше соответствующей ширины подушки на величину перемещения оси вертикального валка. Обеспечивается возможность смещения осей вертикальных валков относительно плоскости осей горизонтальных валков и перемещения вертикального валка по или против направления прокатки относительно плоскости осей горизонтальных валков на величину, необходимую для прокатки рельсов и двутавровых профилей. 4 ил

Coulomb dissociation of O-16 into He-4 and C-12

We measured the Coulomb dissociation of O-16 into He-4 and C-12 within the FAIR Phase-0 program at GSI Helmholtzzentrum fur Schwerionenforschung Darmstadt, Germany. From this we will extract the photon dissociation cross section O-16(alpha,gamma)C-12, which is the time reversed reaction to C-12(alpha,gamma)O-16. With this indirect method, we aim to improve on the accuracy of the experimental data at lower energies than measured so far. The expected low cross section for the Coulomb dissociation reaction and close magnetic rigidity of beam and fragments demand a high precision measurement. Hence, new detector systems were built and radical changes to the (RB)-B-3 setup were necessary to cope with the high-intensity O-16 beam. All tracking detectors were designed to let the unreacted O-16 ions pass, while detecting the C-12 and He-4

Study of the B−→Λc+Λˉc−K−B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-} decay

The decay $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ is studied in proton-proton collisions at a center-of-mass energy of $\sqrt{s}=13$ TeV using data corresponding to an integrated luminosity of 5 $\mathrm{fb}^{-1}$ collected by the LHCb experiment. In the $\Lambda_{c}^+ K^{-}$ system, the $\Xi_{c}(2930)^{0}$ state observed at the BaBar and Belle experiments is resolved into two narrower states, $\Xi_{c}(2923)^{0}$ and $\Xi_{c}(2939)^{0}$, whose masses and widths are measured to be $$m(\Xi_{c}(2923)^{0}) = 2924.5 \pm 0.4 \pm 1.1 \,\mathrm{MeV}, \\ m(\Xi_{c}(2939)^{0}) = 2938.5 \pm 0.9 \pm 2.3 \,\mathrm{MeV}, \\ \Gamma(\Xi_{c}(2923)^{0}) = \phantom{000}4.8 \pm 0.9 \pm 1.5 \,\mathrm{MeV},\\ \Gamma(\Xi_{c}(2939)^{0}) = \phantom{00}11.0 \pm 1.9 \pm 7.5 \,\mathrm{MeV},$$ where the first uncertainties are statistical and the second systematic. The results are consistent with a previous LHCb measurement using a prompt $\Lambda_{c}^{+} K^{-}$ sample. Evidence of a new $\Xi_{c}(2880)^{0}$ state is found with a local significance of $3.8\,\sigma$, whose mass and width are measured to be $2881.8 \pm 3.1 \pm 8.5\,\mathrm{MeV}$ and $12.4 \pm 5.3 \pm 5.8 \,\mathrm{MeV}$, respectively. In addition, evidence of a new decay mode $\Xi_{c}(2790)^{0} \to \Lambda_{c}^{+} K^{-}$ is found with a significance of $3.7\,\sigma$. The relative branching fraction of $B^{-} \to \Lambda_{c}^{+} \bar{\Lambda}_{c}^{-} K^{-}$ with respect to the $B^{-} \to D^{+} D^{-} K^{-}$ decay is measured to be $2.36 \pm 0.11 \pm 0.22 \pm 0.25$, where the first uncertainty is statistical, the second systematic and the third originates from the branching fractions of charm hadron decays.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-028.html (LHCb public pages

Measurement of the ratios of branching fractions R(D∗)\mathcal{R}(D^{*}) and R(D0)\mathcal{R}(D^{0})

The ratios of branching fractions $\mathcal{R}(D^{*})\equiv\mathcal{B}(\bar{B}\to D^{*}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(\bar{B}\to D^{*}\mu^{-}\bar{\nu}_{\mu})$ and $\mathcal{R}(D^{0})\equiv\mathcal{B}(B^{-}\to D^{0}\tau^{-}\bar{\nu}_{\tau})/\mathcal{B}(B^{-}\to D^{0}\mu^{-}\bar{\nu}_{\mu})$ are measured, assuming isospin symmetry, using a sample of proton-proton collision data corresponding to 3.0 fb${ }^{-1}$ of integrated luminosity recorded by the LHCb experiment during 2011 and 2012. The tau lepton is identified in the decay mode $\tau^{-}\to\mu^{-}\nu_{\tau}\bar{\nu}_{\mu}$. The measured values are $\mathcal{R}(D^{*})=0.281\pm0.018\pm0.024$ and $\mathcal{R}(D^{0})=0.441\pm0.060\pm0.066$, where the first uncertainty is statistical and the second is systematic. The correlation between these measurements is $\rho=-0.43$. Results are consistent with the current average of these quantities and are at a combined 1.9 standard deviations from the predictions based on lepton flavor universality in the Standard Model.Comment: All figures and tables, along with any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-039.html (LHCb public pages

Multidifferential study of identified charged hadron distributions in ZZ-tagged jets in proton-proton collisions at s=\sqrt{s}=13 TeV

Jet fragmentation functions are measured for the first time in proton-proton collisions for charged pions, kaons, and protons within jets recoiling against a $Z$ boson. The charged-hadron distributions are studied longitudinally and transversely to the jet direction for jets with transverse momentum 20 $< p_{\textrm{T}} < 100$ GeV and in the pseudorapidity range $2.5 < \eta < 4$. The data sample was collected with the LHCb experiment at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.64 fb$^{-1}$. Triple differential distributions as a function of the hadron longitudinal momentum fraction, hadron transverse momentum, and jet transverse momentum are also measured for the first time. This helps constrain transverse-momentum-dependent fragmentation functions. Differences in the shapes and magnitudes of the measured distributions for the different hadron species provide insights into the hadronization process for jets predominantly initiated by light quarks.Comment: All figures and tables, along with machine-readable versions and any supplementary material and additional information, are available at https://cern.ch/lhcbproject/Publications/p/LHCb-PAPER-2022-013.html (LHCb public pages

Coulomb dissociation of 16O into 4He and 12C

We measured the Coulomb dissociation of 16O into 4He and 12C at the R3B setup in a first campaign within FAIR Phase 0 at GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt. The goal was to improve the accuracy of the experimental data for the 12C(a,?)16O fusion reaction and to reach lower center-ofmass energies than measured so far. The experiment required beam intensities of 109 16O ions per second at an energy of 500 MeV/nucleon. The rare case of Coulomb breakup into 12C and 4He posed another challenge: The magnetic rigidities of the particles are so close because of the same mass-To-charge-number ratio A/Z = 2 for 16O, 12C and 4He. Hence, radical changes of the R3B setup were necessary. All detectors had slits to allow the passage of the unreacted 16O ions, while 4He and 12C would hit the detectors' active areas depending on the scattering angle and their relative energies. We developed and built detectors based on organic scintillators to track and identify the reaction products with sufficient precision

Studies of Ξ+c production in pPb collisions

In this thesis I report the studies of production of Ξc+, a baryon made of usc quarks in proton-lead collisions at a centre-of-mass energy 8.16 TeV measured with LHCb detector at CERN. The studies are based on samples of proton-lead and lead-proton collision data, corresponding to an integrated luminosity of 12.5 and 17.4 nb-1, respectively, collected by the LHCb detector in 2016. The Ξc+ events are reconstructed in the detector through the decay of the Ξc+ baryon in a proton, a kaon and a pion. The analysis is performed over the transverse momentum range 2.0 < pT < 12.0 GeV/c in the regions of rapidity from 1.5 to 4.0 and from -5.0 to -2.5. I present the measurements of the Ξc+ cross-section, production ratios of Ξc+/Λc+ and Ξc+/D0 and forward-backward asymmetry. The results are compared to the latest theoretical predictions. These measurements can provide important information on the hadronisation of charm hadrons, as well as on the hadron structure. Since the Ξc+ contains s quark, the enhancement can be an indication of Quark Gluon Plasma formation

Initial Stages 2021

In 2018, LHCb recorded ~210 microbarn^{-1} integrated luminosity of PbPb collisions at sqrt(s_NN) = 5.02 TeV. With an increase of the luminosity by a factor 20 compared to the previous 2015 PbPb dataset, precise measurements on photo-produced charmonia in ultra-peripheral collisions are foreseen. Moreover, the great momentum resolution of the detector allows to study photo-produced J/psi in collisions with a nuclear overlap. This new type of probe is sensitive to the geometry of the collisions but also to the electromagnetic field of the Pb nuclei. In this talk, we present the latest results on photo-production obtained by LHCb measurements in peripheral and ultra-peripheral PbPb collisions

Studies on charm-strange baryon Ξc+ in 8.16 TeV pPb collisions with LHCb

The Ξc+ baryon is an open charm state comprised of an up, strange, and charm quark. For its peculiar composition with the presence of the strange quark, studies of baryon-to-baryon ratio of Ξc+ to Λc+ can provide valuable information on charm hadronization mechanisms, and possibly observe strangeness enhancement in small systems. We present the first study of Ξc+/Λc+ ratio in proton lead and lead proton collisions at the √s=8.16 TeV with the LHCb experiment. The baryons are reconstructed in their decay with a proton, a kaon, and a pion in about 30 nb−1 of data. The results will be compared to existing measurements in other collision systems and at different energies, and to recent theoretical predictions

LHCb: Heavy ion physics results and prospects

Here, we report on the results and prospects of the LHCb experiment at CERN as well as the upgrades of the LHCb detector within the scope of heavy-ion physics. A particular attention will be given to the extension of the fixed-target program and to the performance of the detector in high-occupancy nucleus–nucleus collisions. The technical description will be followed by a discussion of the results and the prospects for heavy-ion physics in fixed-target and collider mode