The LHCb Detector

Author(s):  
Daniel O’Hanlon
Keyword(s):  
2019 ◽  
Vol 82 (9) ◽  
pp. 1273-1280 ◽  
Author(s):  
G. E. Gavrilov ◽  
O. E. Maev ◽  
D. A. Maisuzenko ◽  
S. A. Nasybulin
Keyword(s):  

2020 ◽  
Vol 2020 (12) ◽  
Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  

Abstract The shape of the $$ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $$ B s 0 → D s ∗ − μ + ν μ differential decay rate is obtained as a function of the hadron recoil parameter using proton-proton collision data at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 1.7 fb−1 collected by the LHCb detector. The $$ {B}_s^0\to {D}_s^{\ast -}{\mu}^{+}{\nu}_{\mu } $$ B s 0 → D s ∗ − μ + ν μ decay is reconstructed through the decays $$ {D}_s^{\ast -}\to {D}_s^{-}\gamma $$ D s ∗ − → D s − γ and $$ {D}_s^{-}\to {K}^{-}{K}^{+}{\pi}^{-} $$ D s − → K − K + π − . The differential decay rate is fitted with the Caprini-Lellouch-Neubert (CLN) and Boyd-Grinstein-Lebed (BGL) parametrisations of the form factors, and the relevant quantities for both are extracted.


2019 ◽  
Vol 214 ◽  
pp. 05040
Author(s):  
Concezio Bozzi ◽  
Sébastien Ponce ◽  
Stefan Roiser

The LHCb detector will be upgraded for the LHC Run 3. The new, full software trigger must be able to sustain the 30MHz proton-proton inelastic collision rate. The Gaudi framework currently used in LHCb has been re-engineered in order to enable the efficient usage of vector registers and of multi-and many-core architectures. This contribution presents the critical points that had to be tackled, the current status of the core software framework and an outlook of the work program that will address the challenges of the software trigger.


2021 ◽  
Vol 251 ◽  
pp. 04009
Author(s):  
Roel Aaij ◽  
Daniel Hugo Cámpora Pérez ◽  
Tommaso Colombo ◽  
Conor Fitzpatrick ◽  
Vladimir Vava Gligorov ◽  
...  

The upgraded LHCb detector, due to start datataking in 2022, will have to process an average data rate of 4 TB/s in real time. Because LHCb’s physics objectives require that the full detector information for every LHC bunch crossing is read out and made available for real-time processing, this bandwidth challenge is equivalent to that of the ATLAS and CMS HL-LHC software read-out, but deliverable five years earlier. Over the past six years, the LHCb collaboration has undertaken a bottom-up rewrite of its software infrastructure, pattern recognition, and selection algorithms to make them better able to efficiently exploit modern highly parallel computing architectures. We review the impact of this reoptimization on the energy efficiency of the realtime processing software and hardware which will be used for the upgrade of the LHCb detector. We also review the impact of the decision to adopt a hybrid computing architecture consisting of GPUs and CPUs for the real-time part of LHCb’s future data processing. We discuss the implications of these results on how LHCb’s real-time power requirements may evolve in the future, particularly in the context of a planned second upgrade of the detector.


2021 ◽  
Author(s):  
Martina Pili ◽  
Keyword(s):  

2021 ◽  
Vol 81 (6) ◽  
Author(s):  
V. P. Gonçalves ◽  
D. E. Martins ◽  
M. S. Rangel

AbstractThe production of axionlike particles (ALPs) with small masses in ultraperipheral Pb–p and Pb–Pb collisions at the LHC is investigated. The cross section and kinematical distributions associated to the diphoton final state produced in the $$\gamma \gamma \rightarrow a \rightarrow \gamma \gamma $$ γ γ → a → γ γ subprocesses are estimated considering a realistic set of kinematical cuts. A detailed analysis of the backgrounds is performed and the expected sensitivity to the ALP production is derived. Our results demonstrate that a future experimental analysis of the exclusive diphoton production for the forward rapidities probed by the LHCb detector can improve the existing exclusion limits on the ALP–photon coupling in the mass range 2 GeV $$\le m_a \le $$ ≤ m a ≤ 5 GeV.


Author(s):  
R. Aaij ◽  
◽  
C. Abellán Beteta ◽  
T. Ackernley ◽  
B. Adeva ◽  
...  

AbstractA search for the doubly charmed baryon $$\Xi_{cc}^+$$Ξcc+ is performed through its decay to the $$\Lambda_c^ + {K^ -}{\pi ^ +}$$Λc+K−π+ final state, using proton-proton collision data collected with the LHCb detector at centre-of-mass energies of 7, 8 and 13 TeV. The data correspond to a total integrated luminosity of 9 fb−1. No significant signal is observed in the mass range from 3.4 to 3.8 GeV/c2. Upper limits are set at 95% credibility level on the ratio of the $$\Xi_{cc}^+$$Ξcc+ production cross-section times the branching fraction to that of $$\Lambda_c^ + $$Λc+ and $$\Xi_{cc}^{+ +}$$Ξcc++ baryons. The limits are determined as functions of the $$\Xi_{cc}^+$$Ξcc+ mass for different lifetime hypotheses, in the rapidity range from 2.0 to 4.5 and the transverse momentum range from 4 to 15 GeV/c.


2016 ◽  
Vol 127 ◽  
pp. 00007 ◽  
Author(s):  
Agnieszka Dziurda
Keyword(s):  

2019 ◽  
Vol 34 (13) ◽  
pp. 1950090 ◽  
Author(s):  
M. Ajaz ◽  
M. Bilal ◽  
Y. Ali ◽  
M. K. Suleymanov ◽  
K. H. Khan

The pseudorapidity [Formula: see text] dependence of charged-particles ratios in three transverse momentum [Formula: see text] regions, obtained by hadron production models, in proton–proton collisions at 7 TeV are compared with the measurements of LHCb detector. Compared to the experimental data, the [Formula: see text] ratios are independent of [Formula: see text] and [Formula: see text] and are very well predicted by all models (DPMJETIII, EPOS1.99, EPOS-LHC, HIJING1.383, QGSJETII-04 and Sibyll2.3c). All models predict the [Formula: see text] ratio at low [Formula: see text] for [Formula: see text], but underestimate afterward while reproducing the experimental data at medium and high [Formula: see text] very well. The [Formula: see text] ratio is described by the models very well at high [Formula: see text] in the low and medium [Formula: see text] region. At high [Formula: see text], models predict the experimental data well, except Sibyll2.3c that slightly overestimates. The [Formula: see text] ratio is predicted by EPOS1.99, HIJING and Sibyll at low [Formula: see text] and EPOS-LHC, EPOS1.99 and Sibyll predicted at high [Formula: see text] for low [Formula: see text]. For medium [Formula: see text], EPOS1.99 and Sibyll predict very well for [Formula: see text] while EPOS-LHC and HIJING models reproduce the data for [Formula: see text]. All models underpredict the [Formula: see text] ratio for [Formula: see text]. For the [Formula: see text] and [Formula: see text] ratios, only Sibyll and EPOS1.99 models could reproduce some regions of [Formula: see text] and [Formula: see text]. None of the models satisfactorily predict all the ratios. the same particle ratios are well described by most of the models while the discrepancies occur mostly in predicting the different particles ratios.


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