Invariant mass distributions of B+pi and B0pi+ combinations are investigated in order to study excited B mesons. The analysis is based on a data sample corresponding to 3.0 fb1 of pp collision data, recorded by the LHCb detector at centreofmass energies of 7 and 8 TeV. Precise measurements of the masses and widths of the B_1(5721)^(0,+) and B_2*(5747)^(0,+) states are reported. Clear enhancements, particularly prominent at high pion transverse momentum, are seen over background in the mass range 58506000 MeV in both B+pi and B0pi+ combinations. The structures are consistent with the presence of four excited B mesons, labelled B_J(5840)^(0,+) and B_J(5960)^(0,+), whose masses and widths are obtained under different hypotheses for their quantum numbers.
Mass predictions of the excited $ B $ states [10,3,4,5,6,7,8,9]. The boxes cover the range of predictions for the masses of each state, and the red dots indicate the measured values. The horizontal lines correspond to the $B\pi$ (red) and $B^*\pi$ (blue) thresholds. 
Fig1.pdf [18 KiB] HiDef png [481 KiB] Thumbnail [170 KiB] *.C file 

Mass distributions of the $ B ^+$ and $ B ^0$ candidates reconstructed through (a) $ B ^+ \rightarrow \overline{ D }{} ^0 (\pi^+,\pi^+\pi^+\pi^)$, (b) $ B ^+ \rightarrow J/\psi K^+$, (c) $ B ^0 \rightarrow D ^ (\pi^+,\pi^+\pi^+\pi^)$, and (d) $ B ^0 \rightarrow J/\psi K ^{*0} $ decays. The $ { J \mskip 3mu/\mskip 2mu\psi \mskip 2mu}$ , $\overline{ D }{} ^0$ and $ D ^$ masses are constrained to their world average values [2]. Results of fits are superimposed for illustration. The signal (dotdashed red line) is modelled with a double Crystal Ball [41] distribution, while the background (dashed black line) is modelled with\ a secondorder polynomial. The total fit is shown as a solid blue line. 
Fig2a.pdf [23 KiB] HiDef png [189 KiB] Thumbnail [59 KiB] *.C file 

Fig2b.pdf [22 KiB] HiDef png [185 KiB] Thumbnail [57 KiB] *.C file 

Fig2c.pdf [23 KiB] HiDef png [216 KiB] Thumbnail [69 KiB] *.C file 

Fig2d.pdf [23 KiB] HiDef png [211 KiB] Thumbnail [67 KiB] *.C file 

Distributions of the $Q$ values of the $ B ^{**}$ candidates after the selection for the (top) $ B ^+ $ and (bottom) $ B ^0 $ candidates. The white histograms represent the RS combinations, while the overlaid shaded red histograms represent the WS combinations. The right hand plots are made after applying an additional requirement of $ p_{\rm T} >2 \mathrm{\,Ge V} $ on the companion pion. 
Fig3.pdf [33 KiB] HiDef png [699 KiB] Thumbnail [122 KiB] *.C file 

Result of the fits to the $Q$value distributions for (top) $ B ^+ \pi ^ $ and (bottom) $ B ^0 \pi ^+ $ candidates. The components are labelled in the legend. The normalised residuals (pulls) of the difference between the fit results and the data points, divided by their uncertainties, are shown underneath each plot. 
Fig4a.pdf [106 KiB] HiDef png [360 KiB] Thumbnail [108 KiB] *.C file 

Fig4b.pdf [105 KiB] HiDef png [349 KiB] Thumbnail [103 KiB] *.C file 

Result of the fit to (left) $ B ^+ \pi ^ $ and (right) $ B ^0 \pi ^+ $ candidates, split into (top to bottom) low, medium and high $p_{\rm T}$ bins, with ranges as labelled on the plots. The components are labelled in the legends. The fit pulls are shown underneath each plot. 
Fig5a.pdf [64 KiB] HiDef png [334 KiB] Thumbnail [100 KiB] *.C file 

Fig5b.pdf [65 KiB] HiDef png [344 KiB] Thumbnail [101 KiB] *.C file 

Fig5c.pdf [66 KiB] HiDef png [361 KiB] Thumbnail [106 KiB] *.C file 

Fig5d.pdf [66 KiB] HiDef png [376 KiB] Thumbnail [108 KiB] *.C file 

Fig5e.pdf [67 KiB] HiDef png [414 KiB] Thumbnail [116 KiB] *.C file 

Fig5f.pdf [66 KiB] HiDef png [418 KiB] Thumbnail [116 KiB] *.C file 

Animated gif made out of all figures. 
PAPER2014067.gif Thumbnail 
Allowed decay modes for the excited $ B $ states. 
Table_1.pdf [42 KiB] HiDef png [53 KiB] Thumbnail [8 KiB] tex code 

Results of the fits when two RBW functions are used for the $B_J(5840)^{0,+}$ and $B_J(5960)^{0,+}$ states (empirical model). The mean $\mu$ of each peak is given together with the width $\Gamma$ and the yield $N_{\textrm{state}}$. The parameters related to the AP and WS components are suppressed for brevity. All uncertainties are statistical only. Units of $\mathrm{\,Me V}$ for $\mu$ and $\Gamma$ are implied. 
Table_2.pdf [77 KiB] HiDef png [206 KiB] Thumbnail [33 KiB] tex code 

Results of the fits when the natural spinparity hypothesis is assigned to (top quadruplet) the $B_J(5840)^{0,+}$ state or (bottom quadruplet) the $B_J(5960)^{0,+}$ state, so that three RBW shapes are used to model the broad resonances in the fit. The mean $\mu$ of each peak is given together with the width $\Gamma$. All uncertainties are statistical only. Units of $\mathrm{\,Me V}$ for $\mu$ and $\Gamma$ are implied. 
Table_3.pdf [49 KiB] HiDef png [183 KiB] Thumbnail [31 KiB] tex code 

Systematic uncertainties on the results of the fit to the $ B ^+ \pi ^ $ candidates. Units of $\mathrm{\,Me V}$ for $\mu$ and $\Gamma$ are implied. 
Table_4.pdf [58 KiB] HiDef png [224 KiB] Thumbnail [35 KiB] tex code 

Systematic uncertainties on the results of the fit to the $ B ^0 \pi ^+ $ candidates. Units of $\mathrm{\,Me V}$ for $\mu$ and $\Gamma$ are implied. 
Table_5.pdf [58 KiB] HiDef png [221 KiB] Thumbnail [33 KiB] tex code 

Parameters of the $B_J(5840)^{0,+}$ and $B_J(5960)^{0,+}$ states obtained with different fit models. The empirical fit uses two, and the quark model fits three, RBW shapes to model the broad resonances. The listed uncertainties are, from left to right: the statistical uncertainty, the experimental systematic uncertainty, and, where applicable, the uncertainty on the $ B $ meson mass and the uncertainty on the $ B ^{*} B$ mass difference. Note that any state not explicitly labelled as "natural" is considered to have unnatural spinparity (and not to be $0^+$); the reported mass can be converted into the corresponding result under the $0^+$ spinparity assumption by subtracting the $ B ^{*} B$ mass difference. Units of $\mathrm{\,Me V}$ are implied. 
Table_6.pdf [61 KiB] HiDef png [266 KiB] Thumbnail [45 KiB] tex code 

Statistical (top) and systematic (bottom) covariance matrices of the nominal $ B ^+ \pi ^ $ fit, where $\mu$ and $\Gamma$ stand for the mean and width respectively. The parameters related to the AP and WS shapes and the signal yields are suppressed for brevity. Units of $\mathrm{\,Me V}$ for $\mu$ and $\Gamma$ are implied. 
Table_7.pdf [50 KiB] HiDef png [128 KiB] Thumbnail [20 KiB] tex code 

Statistical (top) and systematic (bottom) covariance matrices of the nominal $ B ^0 \pi ^+ $ fit, where $\mu$ and $\Gamma$ stand for the mean and width respectively. The parameters related to the AP and WS shapes and the signal yields are suppressed for brevity. Units of $\mathrm{\,Me V}$ for $\mu$ and $\Gamma$ are implied. 
Table_8.pdf [50 KiB] HiDef png [128 KiB] Thumbnail [20 KiB] tex code 
Supplementary material full pdf 
supple[..].pdf [225 KiB] 

This ZIP file contains supplemetary material for the publication LHCbPAPER2014067. The files are: Supplementary.pdf : An overview of the extra figures *.pdf, *.png, *.eps, *.C : The figures in variuous formats 
Fig6.pdf [57 KiB] HiDef png [455 KiB] Thumbnail [117 KiB] *C file 

Fig7.pdf [21 KiB] HiDef png [578 KiB] Thumbnail [182 KiB] *C file 

Fig8.pdf [21 KiB] HiDef png [626 KiB] Thumbnail [186 KiB] *C file 

Fig9.pdf [21 KiB] HiDef png [598 KiB] Thumbnail [186 KiB] *C file 
Created on 19 April 2019.Citation count from INSPIRE on 24 April 2019.