Precision measurement of the \( {\varXi}_{cc}^{++} \) mass

Abstract

A measurement of the \( {\varXi}_{cc}^{++} \) mass is performed using data collected by the LHCb experiment between 2016 and 2018 in pp collisions at a centre-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 5.6 fb1. The \( {\varXi}_{cc}^{++} \) candidates are reconstructed via the decay modes \( {\varXi}_{cc}^{++}\to {\varLambda}_c^{+}{K}^{-}{\pi}^{+}{\pi}^{+} \) and \( {\varXi}_{cc}^{++}\to {\varXi}_c^{+}{\pi}^{+} \). The result, 3621.55 ± 0.23 (stat) ± 0.30 (syst) MeV/c2, is the most precise measurement of the \( {\varXi}_{cc}^{++} \) mass to date.

A preprint version of the article is available at ArXiv.

References

  1. [1]

    M. Gell-Mann, A schematic model of baryons and mesons, Phys. Lett.8 (1964) 214 [INSPIRE].

    Google Scholar 

  2. [2]

    G. Zweig, An SU3model for strong interaction symmetry and its breaking. Version 1, CERN-TH-401 (1964).

  3. [3]

    G. Zweig, An SU3model for strong interaction symmetry and its breaking. Version 2, CERN-TH-412 (1964).

  4. [4]

    LHCb collaboration, Observation of the doubly charmed baryon \( {\Xi}_{cc}^{++} \), Phys. Rev. Lett.119 (2017) 112001 [arXiv:1707.01621] [INSPIRE].

  5. [5]

    LHCb collaboration, First observation of the doubly charmed baryon decay \( {\Xi}_{cc}^{++}\to {\Xi}_c^{+}{\pi}^{+} \), Phys. Rev. Lett.121 (2018) 162002 [arXiv:1807.01919] [INSPIRE].

  6. [6]

    D. Ebert, R.N. Faustov, V.O. Galkin and A.P. Martynenko, Mass spectra of doubly heavy baryons in the relativistic quark model, Phys. Rev.D 66 (2002) 014008 [hep-ph/0201217] [INSPIRE].

  7. [7]

    W. Roberts and M. Pervin, Heavy baryons in a quark model, Int. J. Mod. Phys.A 23 (2008) 2817 [arXiv:0711.2492] [INSPIRE].

    Google Scholar 

  8. [8]

    M. Karliner and J.L. Rosner, Baryons with two heavy quarks: Masses, production, decays and detection, Phys. Rev.D 90 (2014) 094007 [arXiv:1408.5877] [INSPIRE].

  9. [9]

    D.-H. He et al., Evaluation of spectra of baryons containing two heavy quarks in bag model, Phys. Rev.D 70 (2004) 094004 [hep-ph/0403301] [INSPIRE].

  10. [10]

    A. Valcarce, H. Garcilazo and J. Vijande, Towards an understanding of heavy baryon spectroscopy, Eur. Phys. J.A 37 (2008) 217 [arXiv:0807.2973] [INSPIRE].

    Google Scholar 

  11. [11]

    Z.-G. Wang, Analysis of the \( {\frac{1}{2}}^{+} \)doubly heavy baryon states with QCD sum rules, Eur. Phys. J.A 45 (2010) 267 [arXiv:1001.4693] [INSPIRE].

    Google Scholar 

  12. [12]

    V.V. Kiselev and A.K. Likhoded, Baryons with two heavy quarks, Phys. Usp.45 (2002) 455 [hep-ph/0103169] [INSPIRE].

  13. [13]

    J.-R. Zhang and M.-Q. Huang, Doubly heavy baryons in QCD sum rules, Phys. Rev.D 78 (2008) 094007 [arXiv:0810.5396] [INSPIRE].

  14. [14]

    T.M. Aliev, K. Azizi and M. Savci, Doubly heavy spin-1/2 baryon spectrum in QCD, Nucl. Phys.A 895 (2012) 59 [arXiv:1205.2873] [INSPIRE].

    Google Scholar 

  15. [15]

    J.M. Richard and F. Stancu, Double charm hadrons revisited, Bled Workshops Phys.6 (2005) 25 [hep-ph/0511043] [INSPIRE].

  16. [16]

    R. Lewis, N. Mathur and R.M. Woloshyn, Charmed baryons in lattice QCD, Phys. Rev.D 64 (2001) 094509 [hep-ph/0107037] [INSPIRE].

  17. [17]

    UKQCD collaboration, Spectroscopy of doubly charmed baryons in lattice QCD, JHEP07 (2003) 066 [hep-lat/0307025] [INSPIRE].

  18. [18]

    L. Liu, H.-W. Lin, K. Orginos and A. Walker-Loud, Singly and doubly charmed J = 1/2 baryon spectrum from lattice QCD, Phys. Rev.D 81 (2010) 094505 [arXiv:0909.3294] [INSPIRE].

  19. [19]

    X.-Z. Weng, X.-L. Chen and W.-Z. Deng, Masses of doubly heavy-quark baryons in an extended chromomagnetic model, Phys. Rev.D 97 (2018) 054008 [arXiv:1801.08644] [INSPIRE].

  20. [20]

    Q. Li, C.-H. Chang, S.-X. Qin and G.-L. Wang, The mass spectra and wave functions for the doubly heavy baryons with JP = 1+heavy diquark core, Chin. Phys.C 44 (2020) 013102 [arXiv:1903.02282] [INSPIRE].

  21. [21]

    Z.-G. Wang, Analysis of the doubly heavy baryon states and pentaquark states with QCD sum rules, Eur. Phys. J.C 78 (2018) 826 [arXiv:1808.09820] [INSPIRE].

    Google Scholar 

  22. [22]

    Q.-F. Lü, K.-L. Wang, L.-Y. Xiao and X.-H. Zhong, Mass spectra and radiative transitions of doubly heavy baryons in a relativized quark model, Phys. Rev.D 96 (2017) 114006 [arXiv:1708.04468] [INSPIRE].

  23. [23]

    LHCb collaboration, The LHCb detector at the LHC, 2008 JINST3 S08005 [INSPIRE].

  24. [24]

    LHCb collaboration, LHCb detector performance, Int. J. Mod. Phys.A 30 (2015) 1530022 [arXiv:1412.6352] [INSPIRE].

  25. [25]

    R. Aaij et al., Performance of the LHCb vertex locator, 2014 JINST9 P09007 [arXiv:1405.7808] [INSPIRE].

  26. [26]

    R. Arink et al., Performance of the LHCb outer tracker, 2014 JINST9 P01002 [arXiv:1311.3893] [INSPIRE].

  27. [27]

    P. d’Argent et al., Improved performance of the LHCb outer tracker in LHC Run 2, 2017 JINST12 P11016 [arXiv:1708.00819] [INSPIRE].

  28. [28]

    LHCb collaboration, Measurement of the \( {\Lambda}_b^0,{\Xi}_b^{-} \)and \( {\varOmega}_b^{-} \)baryon masses, Phys. Rev. Lett.110 (2013) 182001 [arXiv:1302.1072] [INSPIRE].

  29. [29]

    LHCb collaboration, Precision measurement of D meson mass differences, JHEP06 (2013) 065 [arXiv:1304.6865] [INSPIRE].

  30. [30]

    M. Adinolfi et al., Performance of the LHCb RICH detector at the LHC, Eur. Phys. J.C 73 (2013) 2431 [arXiv:1211.6759] [INSPIRE].

    Google Scholar 

  31. [31]

    A.A. Alves Jr. et al., Performance of the LHCb muon system, 2013 JINST8 P02022 [arXiv:1211.1346] [INSPIRE].

  32. [32]

    R. Aaij et al., The LHCb trigger and its performance in 2011, 2013 JINST8 P04022 [arXiv:1211.3055] [INSPIRE].

  33. [33]

    G. Dujany and B. Storaci, Real-time alignment and calibration of the LHCb Detector in Run II, J. Phys. Conf. Ser.664 (2015) 082010 [INSPIRE].

  34. [34]

    T. Sjöstrand, S. Mrenna and P.Z. Skands, A brief introduction to PYTHIA 8.1, Comput. Phys. Commun.178 (2008) 852 [arXiv:0710.3820] [INSPIRE].

  35. [35]

    I. Belyaev et al., Handling of the generation of primary events in Gauss, the LHCb simulation framework, J. Phys. Conf. Ser.331 (2011) 032047 [INSPIRE].

  36. [36]

    C.-H. Chang, J.-X. Wang and X.-G. Wu, GENXICC2.0: an upgraded version of the generator for hadronic production of double heavy baryons Ξcc, Ξbcand Ξbb, Comput. Phys. Commun.181 (2010) 1144 [arXiv:0910.4462] [INSPIRE].

  37. [37]

    X.-Y. Wang and X.-G. Wu, GENXICC2.1: an improved version of GENXICC for hadronic production of doubly heavy baryons, Comput. Phys. Commun.184 (2013) 1070 [arXiv:1210.3458] [INSPIRE].

  38. [38]

    D.J. Lange, The EvtGen particle decay simulation package, Nucl. Instrum. Meth.A 462 (2001) 152 [INSPIRE].

    Google Scholar 

  39. [39]

    P. Golonka and Z. Was, PHOTOS Monte Carlo: a precision tool for QED corrections in Z and W decays, Eur. Phys. J.C 45 (2006) 97 [hep-ph/0506026] [INSPIRE].

  40. [40]

    GEANT4 collaboration, GEANT4 developments and applications, IEEE Trans. Nucl. Sci.53 (2006) 270.

  41. [41]

    GEANT4 collaboration, GEANT4: a simulation toolkit, Nucl. Instrum. Meth.A 506 (2003) 250 [INSPIRE].

  42. [42]

    M. Clemencic et al., The LHCb simulation application, Gauss: design, evolution and experience, J. Phys. Conf. Ser.331 (2011) 032023 [INSPIRE].

  43. [43]

    G.A. Cowan, D.C. Craik and M.D. Needham, RapidSim: an application for the fast simulation of heavy-quark hadron decays, Comput. Phys. Commun.214 (2017) 239 [arXiv:1612.07489] [INSPIRE].

    Google Scholar 

  44. [44]

    L. Breiman, J.H. Friedman, R.A. Olshen, and C.J. Stone, Classification and regression trees, Wadsworth international group, Belmont U.S.A. (1984).

  45. [45]

    Y. Freund and R.E. Schapire, A decision-theoretic generalization of on-line learning and an application to boosting, J. Comput. Syst. Sci.55 (1997) 119.

    Google Scholar 

  46. [46]

    H. Voss, A. Hoecker, J. Stelzer and F. Tegenfeldt, TMVA — Toolkit for Multivariate Data Analysis with ROOT, PoS(ACAT)040.

  47. [47]

    A. Hocker et al., TMVA — Toolkit for Multivariate Data Analysis, physics/0703039 [INSPIRE].

  48. [48]

    BaBar collaboration, A precision measurement of the \( {\Lambda}_c^{+} \)baryon mass, Phys. Rev.D 72 (2005) 052006 [hep-ex/0507009] [INSPIRE].

  49. [49]

    Particle Data Group collaboration, Review of particle physics, Phys. Rev.D 98 (2018) 030001 [INSPIRE].

  50. [50]

    LHCb collaboration, Precision measurement of the mass and lifetime of the \( {\Xi}_b^0 \)baryon, Phys. Rev. Lett.113 (2014) 032001 [arXiv:1405.7223] [INSPIRE].

  51. [51]

    T. Skwarnicki, A study of the radiative cascade transitions between the ϒ′ and ϒ resonances, Ph.D. thesis, Institute of Nuclear Physics, Krakow, Poland (1986) [DESY-F31-86-02].

  52. [52]

    M. Pivk and F.R. Le Diberder, SPlot: a statistical tool to unfold data distributions, Nucl. Instrum. Meth.A 555 (2005) 356 [physics/0402083] [INSPIRE].

  53. [53]

    L. Lyons, D. Gibaut and P. Clifford, How to combine correlated estimates of a single physical quantity, Nucl. Instrum. Meth.A 270 (1988) 110 [INSPIRE].

    Google Scholar 

  54. [54]

    A. Valassi, Combining correlated measurements of several different physical quantities, Nucl. Instrum. Meth.A 500 (2003) 391 [INSPIRE].

    Google Scholar 

Download references

Open Access

This article is distributed under the terms of the Creative Commons Attribution License (CC-BY 4.0), which permits any use, distribution and reproduction in any medium, provided the original author(s) and source are credited

Author information

Affiliations

Authors