The observation of associated production of an $Υ$(1S) meson with a Z boson and a measurement of the ratio of its fiducial cross section to the fiducial cross section of the Z boson are presented. Both the $Υ$(1S) meson and the Z boson are identified via decays into a pair of opposite-sign muons. The analysis is based on proton-proton (pp) collision data at $\sqrt{s}$ = 13 TeV, collected with the CMS detector in 2016$-$2018 and corresponding to an integrated luminosity of 138 fb$^{-1}$. Using the production of the Z boson decaying into four muons as a normalization channel, the ratio of the fiducial cross sections $σ$(pp $\to$ Z $+$$Υ$(1S))$\mathcal{B}$(Z $\to$$μ^+μ^-$)$\mathcal{B}$($Υ$(1S) $\to$$μ^+μ^-$ ) to $σ$(pp $\to$ Z)$\mathcal{B}$(Z $\to$ 4$μ$) is measured to be $\mathcal{R}_{\mathrm{Z+Υ}\mathrm{(1S)}}$ = (21.1 $\pm$ 55 (stat) $\pm$ 0.6 (syst) $\times$ 10$^{-3}$), where stat and syst denote the statistical and systematic uncertainties, respectively. The result is used to extract the effective double-parton scattering cross section $σ_\text{eff}$ = 13.0$^{+7.7}_{-3.4}$. In addition, for the first time, $σ_\text{eff}$ is measured in bins of the transverse momentum of the $Υ$(1S) meson or of the Z boson.
$\sigma(\mathrm{pp}\to\mathrm{Z+Y(1S)})\mathcal{B}(\mathrm{Z}\to\mu\mu)\mathcal{B}(\mathrm{Y(1S)}\to\mu\mu) / \sigma(\mathrm{pp}\to\mathrm{Z})\mathcal{B}(\mathrm{Z}\to\mu\mu\mu\mu)$
DPS $\sigma(\mathrm{pp}\to\mathrm{Z+Y(1S)})\mathcal{B}(\mathrm{Z}\to\mu\mu)\mathcal{B}(\mathrm{Y(1S)}\to\mu\mu) / \sigma(\mathrm{pp}\to\mathrm{Z})\mathcal{B}(\mathrm{Z}\to\mu\mu\mu\mu)$
$\sigma(\mathrm{pp}\to\mathrm{Z+Y(1S)})\mathcal{B}(\mathrm{Z}\to\mu\mu)\mathcal{B}(\mathrm{Y(1S)}\to\mu\mu) / \sigma(\mathrm{pp}\to\mathrm{Z})\mathcal{B}(\mathrm{Z}\to\mu\mu\mu\mu)$
At the Large Hadron Collider, the $WbWb$ final state is expected to be dominated by $t\bar{t}$ production with a contribution from single-top processes. Differential cross-sections for $WbWb$ production in the dilepton decay channel are measured at the particle level as a function of various kinematic variables. The analysis is based on data from proton-proton collisions at a centre-of-mass energy of $\sqrt{s} = 13$ TeV, recorded by the ATLAS detector at the Large Hadron Collider over the period from 2015 to 2018, corresponding to an integrated luminosity of 140 fb$^{-1}$. Measurements are performed within the fiducial phase-space defined by the presence of two $b$-jets and one electron and one muon of opposite charges. The differential cross-sections are corrected for detector effects and unfolded to the particle level. Results are compared with predictions from Monte Carlo event generators at next-to-leading order in perturbative quantum chromodynamics. These measurements provide valuable constraints on the modelling of $WbWb$ production and the interference between doubly resonant and singly resonant $WbWb$ production.
- - - - - - - - Overview of HEPData Record - - - - - - - - <br/><br/> <b>Fiducial phase space definitions:</b><br/> <i>Exclusive:</i> <ul> <li> NLEP = 2, EMU, PT > 28 GeV, ABS ETA < 2.5 <li> NJETS >= 2, PT > 25 GeV, ABS ETA < 2.5 <li> NBJETS = 2 </ul><br/> <i>Inclusive:</i> <ul> <li> NLEP = 2, EMU, PT > 28 GeV, ABS ETA < 2.5 <li> NJETS >= 2, PT > 25 GeV, ABS ETA < 2.5 <li> NBJETS >= 2 </ul><br/> <b>Measurements:</b><br/> <i>Exclusive:</i><br/> Spectra: <ul> <li>DSIG/DM_BL_MINIMAX (<a href="159379?table=Table 1">Table 1</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (<a href="159379?table=Table 4">Table 4</a> ) <li>SIG (<a href="159379?table=Table 7">Table 7</a> ) </ul><br/> Data statistical covariances: <ul> <li>DSIG/DM_BL_MINIMAX (<a href="159379?table=Table 2">Table 2</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (<a href="159379?table=Table 5">Table 5</a> ) <li>SIG (<a href="159379?table=Table 8">Table 8</a> ) </ul><br/> MC statistical covariances: <ul> <li>DSIG/DM_BL_MINIMAX (<a href="159379?table=Table 3">Table 3</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (<a href="159379?table=Table 6">Table 6</a> ) <li>SIG (<a href="159379?table=Table 9">Table 9</a> ) </ul><br/> <b>Particle level:</b><br/> <i>Inclusive:</i><br/> Spectra: <ul> <li>DSIG/Dn_JETS (<a href="159379?table=Table 10">Table 10</a> ) <li>1/SIG*DSIG/Dn_JETS (<a href="159379?table=Table 13">Table 13</a> ) <li>DSIG/DM_BBLL (<a href="159379?table=Table 16">Table 16</a> ) <li>1/SIG*DSIG/DM_BBLL (<a href="159379?table=Table 19">Table 19</a> ) <li>DSIG/DMT_BB4L (<a href="159379?table=Table 22">Table 22</a> ) <li>1/SIG*DSIG/DMT_BB4L (<a href="159379?table=Table 25">Table 25</a> ) <li>DSIG/DPT_BB (<a href="159379?table=Table 28">Table 28</a> ) <li>1/SIG*DSIG/DPT_BB (<a href="159379?table=Table 31">Table 31</a> ) <li>DSIG/DPT_J1 (<a href="159379?table=Table 34">Table 34</a> ) <li>1/SIG*DSIG/DPT_J1 (<a href="159379?table=Table 37">Table 37</a> ) <li>DSIG/DPT_J2 (<a href="159379?table=Table 40">Table 40</a> ) <li>1/SIG*DSIG/DPT_J2 (<a href="159379?table=Table 43">Table 43</a> ) <li>DSIG/DPT_L1 (<a href="159379?table=Table 46">Table 46</a> ) <li>1/SIG*DSIG/DPT_L1 (<a href="159379?table=Table 49">Table 49</a> ) <li>DSIG/DPT_L2 (<a href="159379?table=Table 52">Table 52</a> ) <li>1/SIG*DSIG/DPT_L2 (<a href="159379?table=Table 55">Table 55</a> ) <li>DSIG/DPT_BB4L (<a href="159379?table=Table 58">Table 58</a> ) <li>1/SIG*DSIG/DPT_BB4L (<a href="159379?table=Table 61">Table 61</a> ) <li>DSIG/DPT_BBLL (<a href="159379?table=Table 64">Table 64</a> ) <li>1/SIG*DSIG/DPT_BBLL (<a href="159379?table=Table 67">Table 67</a> ) <li>SIG (<a href="159379?table=Table 70">Table 70</a> ) </ul><br/> Data statistical covariances: <ul> <li>DSIG/Dn_JETS (<a href="159379?table=Table 11">Table 11</a> ) <li>1/SIG*DSIG/Dn_JETS (<a href="159379?table=Table 14">Table 14</a> ) <li>DSIG/DM_BBLL (<a href="159379?table=Table 17">Table 17</a> ) <li>1/SIG*DSIG/DM_BBLL (<a href="159379?table=Table 20">Table 20</a> ) <li>DSIG/DMT_BB4L (<a href="159379?table=Table 23">Table 23</a> ) <li>1/SIG*DSIG/DMT_BB4L (<a href="159379?table=Table 26">Table 26</a> ) <li>DSIG/DPT_BB (<a href="159379?table=Table 29">Table 29</a> ) <li>1/SIG*DSIG/DPT_BB (<a href="159379?table=Table 32">Table 32</a> ) <li>DSIG/DPT_J1 (<a href="159379?table=Table 35">Table 35</a> ) <li>1/SIG*DSIG/DPT_J1 (<a href="159379?table=Table 38">Table 38</a> ) <li>DSIG/DPT_J2 (<a href="159379?table=Table 41">Table 41</a> ) <li>1/SIG*DSIG/DPT_J2 (<a href="159379?table=Table 44">Table 44</a> ) <li>DSIG/DPT_L1 (<a href="159379?table=Table 47">Table 47</a> ) <li>1/SIG*DSIG/DPT_L1 (<a href="159379?table=Table 50">Table 50</a> ) <li>DSIG/DPT_L2 (<a href="159379?table=Table 53">Table 53</a> ) <li>1/SIG*DSIG/DPT_L2 (<a href="159379?table=Table 56">Table 56</a> ) <li>DSIG/DPT_BB4L (<a href="159379?table=Table 59">Table 59</a> ) <li>1/SIG*DSIG/DPT_BB4L (<a href="159379?table=Table 62">Table 62</a> ) <li>DSIG/DPT_BBLL (<a href="159379?table=Table 65">Table 65</a> ) <li>1/SIG*DSIG/DPT_BBLL (<a href="159379?table=Table 68">Table 68</a> ) <li>SIG (<a href="159379?table=Table 71">Table 71</a> ) </ul><br/> MC statistical covariances: <ul> <li>DSIG/Dn_JETS (<a href="159379?table=Table 12">Table 12</a> ) <li>1/SIG*DSIG/Dn_JETS (<a href="159379?table=Table 15">Table 15</a> ) <li>DSIG/DM_BBLL (<a href="159379?table=Table 18">Table 18</a> ) <li>1/SIG*DSIG/DM_BBLL (<a href="159379?table=Table 21">Table 21</a> ) <li>DSIG/DMT_BB4L (<a href="159379?table=Table 24">Table 24</a> ) <li>1/SIG*DSIG/DMT_BB4L (<a href="159379?table=Table 27">Table 27</a> ) <li>DSIG/DPT_BB (<a href="159379?table=Table 30">Table 30</a> ) <li>1/SIG*DSIG/DPT_BB (<a href="159379?table=Table 33">Table 33</a> ) <li>DSIG/DPT_J1 (<a href="159379?table=Table 36">Table 36</a> ) <li>1/SIG*DSIG/DPT_J1 (<a href="159379?table=Table 39">Table 39</a> ) <li>DSIG/DPT_J2 (<a href="159379?table=Table 42">Table 42</a> ) <li>1/SIG*DSIG/DPT_J2 (<a href="159379?table=Table 45">Table 45</a> ) <li>DSIG/DPT_L1 (<a href="159379?table=Table 48">Table 48</a> ) <li>1/SIG*DSIG/DPT_L1 (<a href="159379?table=Table 51">Table 51</a> ) <li>DSIG/DPT_L2 (<a href="159379?table=Table 54">Table 54</a> ) <li>1/SIG*DSIG/DPT_L2 (<a href="159379?table=Table 57">Table 57</a> ) <li>DSIG/DPT_BB4L (<a href="159379?table=Table 60">Table 60</a> ) <li>1/SIG*DSIG/DPT_BB4L (<a href="159379?table=Table 63">Table 63</a> ) <li>DSIG/DPT_BBLL (<a href="159379?table=Table 66">Table 66</a> ) <li>1/SIG*DSIG/DPT_BBLL (<a href="159379?table=Table 69">Table 69</a> ) <li>SIG (<a href="159379?table=Table 72">Table 72</a> ) </ul><br/> Inter-spectra data statistical covariances: <ul> <li>SIG (exclusive) versus DSIG/DM_BL_MINIMAX (exclusive) (<a href="159379?table=Table 73">Table 73</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 74">Table 74</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 75">Table 75</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 76">Table 76</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 77">Table 77</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 78">Table 78</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 79">Table 79</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_L1 (inclusive) (<a href="159379?table=Table 80">Table 80</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_L2 (inclusive) (<a href="159379?table=Table 81">Table 81</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 82">Table 82</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 83">Table 83</a> ) <li>DSIG/DM_BL_MINIMAX (exclusive) versus SIG (inclusive) (<a href="159379?table=Table 84">Table 84</a> ) <li>SIG (exclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 85">Table 85</a> ) <li>SIG (exclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 86">Table 86</a> ) <li>SIG (exclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 87">Table 87</a> ) <li>SIG (exclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 88">Table 88</a> ) <li>SIG (exclusive) versus DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 89">Table 89</a> ) <li>SIG (exclusive) versus DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 90">Table 90</a> ) <li>SIG (exclusive) versus DSIG/DPT_L1 (inclusive) (<a href="159379?table=Table 91">Table 91</a> ) <li>SIG (exclusive) versus DSIG/DPT_L2 (inclusive) (<a href="159379?table=Table 92">Table 92</a> ) <li>SIG (exclusive) versus DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 93">Table 93</a> ) <li>SIG (exclusive) versus DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 94">Table 94</a> ) <li>SIG (exclusive) versus SIG (inclusive) (<a href="159379?table=Table 95">Table 95</a> ) <li>DSIG/DM_BBLL (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 96">Table 96</a> ) <li>DSIG/DM_BBLL (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 97">Table 97</a> ) <li>DSIG/DM_BBLL (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 98">Table 98</a> ) <li>DSIG/DPT_J1 (inclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 99">Table 99</a> ) <li>DSIG/DPT_J2 (inclusive) versus DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 100">Table 100</a> ) <li>DSIG/DPT_L1 (inclusive) versus DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 101">Table 101</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DPT_L1 (inclusive) (<a href="159379?table=Table 102">Table 102</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 103">Table 103</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 104">Table 104</a> ) <li>SIG (inclusive) versus DSIG/DPT_L2 (inclusive) (<a href="159379?table=Table 105">Table 105</a> ) <li>DSIG/DMT_BB4L (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 106">Table 106</a> ) <li>DSIG/DPT_BB (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 107">Table 107</a> ) <li>DSIG/DPT_J1 (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 108">Table 108</a> ) <li>DSIG/DPT_J1 (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 109">Table 109</a> ) <li>DSIG/DPT_J1 (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 110">Table 110</a> ) <li>DSIG/DPT_J2 (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 111">Table 111</a> ) <li>DSIG/DPT_J2 (inclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 112">Table 112</a> ) <li>DSIG/DPT_J2 (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 113">Table 113</a> ) <li>DSIG/DPT_J2 (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 114">Table 114</a> ) <li>DSIG/DPT_L1 (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 115">Table 115</a> ) <li>DSIG/DPT_L1 (inclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 116">Table 116</a> ) <li>DSIG/DPT_L1 (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 117">Table 117</a> ) <li>DSIG/DPT_L1 (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 118">Table 118</a> ) <li>DSIG/DPT_L1 (inclusive) versus DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 119">Table 119</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 120">Table 120</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 121">Table 121</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 122">Table 122</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 123">Table 123</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 124">Table 124</a> ) <li>DSIG/DPT_L2 (inclusive) versus DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 125">Table 125</a> ) <li>DSIG/Dn_JETS (inclusive) versus DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 126">Table 126</a> ) <li>DSIG/DPT_BBLL (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 127">Table 127</a> ) <li>DSIG/DPT_BBLL (inclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 128">Table 128</a> ) <li>DSIG/DPT_BBLL (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 129">Table 129</a> ) <li>DSIG/DPT_BBLL (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 130">Table 130</a> ) <li>DSIG/DPT_J1 (inclusive) versus DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 131">Table 131</a> ) <li>SIG (inclusive) versus DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 132">Table 132</a> ) <li>SIG (inclusive) versus DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 133">Table 133</a> ) <li>SIG (inclusive) versus DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 134">Table 134</a> ) <li>SIG (inclusive) versus DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 135">Table 135</a> ) <li>SIG (inclusive) versus DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 136">Table 136</a> ) <li>SIG (inclusive) versus DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 137">Table 137</a> ) <li>SIG (inclusive) versus DSIG/DPT_L1 (inclusive) (<a href="159379?table=Table 138">Table 138</a> ) <li>SIG (inclusive) versus DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 139">Table 139</a> ) <li>SIG (inclusive) versus DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 140">Table 140</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 141">Table 141</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 142">Table 142</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 143">Table 143</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 144">Table 144</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 145">Table 145</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 146">Table 146</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_L1 (inclusive) (<a href="159379?table=Table 147">Table 147</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_L2 (inclusive) (<a href="159379?table=Table 148">Table 148</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 149">Table 149</a> ) <li>1/SIG*DSIG/DM_BL_MINIMAX (exclusive) versus 1/SIG*DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 150">Table 150</a> ) <li>1/SIG*DSIG/DM_BBLL (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 151">Table 151</a> ) <li>1/SIG*DSIG/DM_BBLL (inclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 152">Table 152</a> ) <li>1/SIG*DSIG/DM_BBLL (inclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 153">Table 153</a> ) <li>1/SIG*DSIG/DPT_J1 (inclusive) versus 1/SIG*DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 154">Table 154</a> ) <li>1/SIG*DSIG/DPT_J2 (inclusive) versus 1/SIG*DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 155">Table 155</a> ) <li>1/SIG*DSIG/DPT_L1 (inclusive) versus 1/SIG*DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 156">Table 156</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DPT_L1 (inclusive) (<a href="159379?table=Table 157">Table 157</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 158">Table 158</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 159">Table 159</a> ) <li>1/SIG*DSIG/DMT_BB4L (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 160">Table 160</a> ) <li>1/SIG*DSIG/DPT_BB (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 161">Table 161</a> ) <li>1/SIG*DSIG/DPT_J1 (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 162">Table 162</a> ) <li>1/SIG*DSIG/DPT_J1 (inclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 163">Table 163</a> ) <li>1/SIG*DSIG/DPT_J1 (inclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 164">Table 164</a> ) <li>1/SIG*DSIG/DPT_J2 (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 165">Table 165</a> ) <li>1/SIG*DSIG/DPT_J2 (inclusive) versus 1/SIG*DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 166">Table 166</a> ) <li>1/SIG*DSIG/DPT_J2 (inclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 167">Table 167</a> ) <li>1/SIG*DSIG/DPT_J2 (inclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 168">Table 168</a> ) <li>1/SIG*DSIG/DPT_L1 (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 169">Table 169</a> ) <li>1/SIG*DSIG/DPT_L1 (inclusive) versus 1/SIG*DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 170">Table 170</a> ) <li>1/SIG*DSIG/DPT_L1 (inclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 171">Table 171</a> ) <li>1/SIG*DSIG/DPT_L1 (inclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 172">Table 172</a> ) <li>1/SIG*DSIG/DPT_L1 (inclusive) versus 1/SIG*DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 173">Table 173</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 174">Table 174</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 175">Table 175</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 176">Table 176</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 177">Table 177</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DPT_J1 (inclusive) (<a href="159379?table=Table 178">Table 178</a> ) <li>1/SIG*DSIG/DPT_L2 (inclusive) versus 1/SIG*DSIG/DPT_J2 (inclusive) (<a href="159379?table=Table 179">Table 179</a> ) <li>1/SIG*DSIG/Dn_JETS (inclusive) versus 1/SIG*DSIG/DPT_BB4L (inclusive) (<a href="159379?table=Table 180">Table 180</a> ) <li>1/SIG*DSIG/DPT_BBLL (inclusive) versus 1/SIG*DSIG/Dn_JETS (inclusive) (<a href="159379?table=Table 181">Table 181</a> ) <li>1/SIG*DSIG/DPT_BBLL (inclusive) versus 1/SIG*DSIG/DM_BBLL (inclusive) (<a href="159379?table=Table 182">Table 182</a> ) <li>1/SIG*DSIG/DPT_BBLL (inclusive) versus 1/SIG*DSIG/DMT_BB4L (inclusive) (<a href="159379?table=Table 183">Table 183</a> ) <li>1/SIG*DSIG/DPT_BBLL (inclusive) versus 1/SIG*DSIG/DPT_BB (inclusive) (<a href="159379?table=Table 184">Table 184</a> ) <li>1/SIG*DSIG/DPT_J1 (inclusive) versus 1/SIG*DSIG/DPT_BBLL (inclusive) (<a href="159379?table=Table 185">Table 185</a> ) </ul>
Absolute differential cross-section as a function of $m^{bl}_{minimax}$ at particle level in the exclusive topology. Note that the values shown here are obtained by propagating the individual uncertainties to the measured cross-sections. The covariance matrices are evaluated using pseudo-experiments for data and MC statistical uncertainties, and added to the individual covariance matrices for the remaining uncertainties, as described in the text. The measured differential cross-section is compared with the prediction obtained with the Powheg+Pythia8 Monte Carlo generator.
Covariance matrix of the absolute differential cross-section as function of $m^{bl}_{minimax}$ at particle level in the exclusive topology, accounting for the data statistical uncertainties.
A measurement of the fiducial cross section of the associated production of a Z boson and a high-$p_\mathrm{T}$ photon, where the Z decays to two neutrinos, and a search for anomalous triple gauge couplings are reported. The results are based on data collected by the CMS experiment at the LHC in proton-proton collisions at $\sqrt{s}$ = 13 TeV during 2016$-$2018, corresponding to an integrated luminosity of 138 fb$^{-1}$. The fiducial Z$γ$ cross section, where a photon with a $p_\mathrm{T}$ greater than 225 GeV is produced in association with a Z, and the Z decays to a $ν\barν$ pair (Z($ν\barν$)$γ$), is measured to be 23.3$^{+1.4}_{-1.3}$ fb, in agreement, within uncertainties, with the standard model prediction. The differential cross section as a function of the photon $p_\mathrm{T}$ has been measured and compared with standard model predictions computed at next-to-leading and at next-to-next-to-leading order in perturbative quantum chromodynamics. Constraints have been placed on the presence of anomalous couplings that affect the ZZ$γ$ and Z$γγ$ vertex using the $p_\mathrm{T}$ spectrum of the photons. The observed 95% confidence level intervals for $CP$-conserving $h_3^γ$ and $h_4^γ$ are determined to be ($-$3.4, 3.5) $\times$ 10$^{-4}$ and ($-$6.8, 6.8) $\times$ 10$^{-7}$, and for $h_3^\mathrm{Z}$ and $h_4^\mathrm{Z}$ they are ($-$2.2, 2.2) $\times$ 10$^{-4}$ and ($-$4.1, 4.2) $\times$ 10$^{-7}$, respectively. These are the strictest limits to date on $h_3^γ$, $h_3^\mathrm{Z}$ and $h_4^\mathrm{Z}$.
Post-fit reconstruction-level photon transverse momentum $p_{T}^{\gamma}$ distribution in the ECAL barrel signal region. The yields correspond to the post-fit expectation from the maximum-likelihood fit used in the analysis, with uncertainties reflecting the post-fit total (stat+syst) uncertainty per bin. Data correspond to the full Run-2 dataset (138 fb$^{-1}$ at $\sqrt{s}=13$ TeV).
Post-fit reconstruction-level photon transverse momentum $p_{T}^{\gamma}$ distribution in the ECAL endcaps signal region. The yields correspond to the post-fit expectation from the maximum-likelihood fit used in the analysis, with uncertainties reflecting the post-fit total (stat+syst) uncertainty per bin. Data correspond to the full Run-2 dataset (138 fb$^{-1}$ at $\sqrt{s}=13$ TeV).
Measured and predicted fiducial cross sections (fb) in the EB, EE, and combined phase space. The fiducial phase space definition follows the analysis selection in the paper. Predictions are shown at NLO (MADGRAPH5_aMC@NLO) and NNLO (MATRIX).
A combined statistical analysis of searches for heavy vector boson resonances decaying into pairs of W, Z, or Higgs bosons, as well as into quark pairs ($\mathrm{q\bar{q}}$, $\mathrm{b\bar{b}}$, $\mathrm{t\bar{t}}$, $\mathrm{t\bar{b}}$) or lepton pairs ($\ell^+\ell^-$, $\ell\barν$), with $\ell =$ e, $μ$, $τ$, is presented. The results are based on proton-proton collision data at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$, collected by the CMS experiment from 2016 to 2018. No significant deviation from the expectations of the standard model is observed. The results are interpreted in the simplified heavy vector triplet (HVT) framework, setting 95% confidence level upper limits on the production cross sections and coupling strengths to standard model particles or the HVT bosons. The results exclude HVT resonances with masses below 5.5 TeV in a weakly coupled scenario, below 4.8 TeV in a strongly coupled scenario, and up to 2.0 TeV in the case of production via vector boson fusion. The combination provides the most stringent constraints to date on new phenomena predicted by the HVT model.
Expected and observed 95% CL upper limits on the V'boson production cross section as functions of the resonance mass mV' shown separately for the V' → quarks category. The limits are evaluated in the HVT model A scenario.
Expected and observed 95% CL upper limits on the V'boson production cross section as functions of the resonance mass mV' shown separately for the V' → leptons category. The limits are evaluated in the HVT model A scenario.
Expected and observed 95% CL upper limits on the V' boson production cross section as functions of the resonance mass mV' shown separately for the V' → bosons category. The limits are evaluated in the HVT model B scenario.
The first observation of electroweak production of a photon in association with two forward jets in proton-proton collisions is presented. The measurement uses data recorded by the CMS experiment at the LHC during 2016$-$2018 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. The analysis is performed in a region enriched in photon production via vector boson fusion, with a requirement on the transverse momentum of the photon to exceed 200 GeV. The cross section is measured to be 202$^{+36}_{-32}$ fb, at a significance with respect to the null hypothesis that exceeds five standard deviations. This is in agreement with the standard model prediction of 177$^{+13}_{-12}$ fb. Differential cross sections are measured as a function of various observables. Limits are set on dimension-6 effective field theory operators that contribute to the WW$γ$ interaction. The observed 95% confidence intervals for the corresponding Warsaw basis Wilson coefficients $c_\mathrm{W}$ and $c_\mathrm{HWB}$ are [$-$0.11, 0.16] and [$-$1.6, 1.5], respectively.
Summary of uncertainties affecting the measurement as extracted from the fit to data. The total uncertainty is obtained by adding individual contributions in quadrature.
The rapidity gap fraction as a function of $p_{\mathrm{T}^{veto}}$ in data and simulated samples for EW $\gamma$jj and QCD $\gamma$jj. The black points with error bars represent the data and their statistical uncertainties. The theory prediction, calculated using Madgraph5_aMC@NLO version 2.6.5 at NLO in QCD together with PYTHIA version 8.240, as well as MC statistical uncertainties are shown by the colored band.
Normalized differential cross sections, compared with the SM predictions, as a function of the absolute value of pseudorapidity of the leading jet in transverse momentum. The SM predictions are obtained using Madgraph5_aMC@NLO version 2.6.5 at NLO in QCD with PYTHIA version 8.240
A search for a new neutral gauge boson, Z', produced in association with one or two jets, including at least one b jet, and decaying into a pair of muons is presented. The analysis uses proton-proton collision data collected with the CMS detector at $\sqrt{s}$ = 13 TeV, corresponding to an integrated luminosity of 138 fb$^{-1}$. No significant deviation from background expectations is observed. Upper limits at 95% confidence level on the product of cross section, branching fraction to dimuons, acceptance, and efficiency, from 0.2 to 2 fb, are set for Z' boson masses between 125 and 350 GeV. Process-dependent products of acceptance and efficiency, and model-independent limits on the signal yield are provided. These are the only results to date in the 125$-$200 GeV mass range and the most stringent for b quark fusion production modes in the 200$-$350 GeV range, complementing inclusive Z' boson searches.
Distributions of $m_{\ell\ell}$ in the $\mathrm{SR_{b}^{mm}}$ SR. Events are divided by the bin width. Simulated signal shapes for $Z'$ boson masses of 125, 200, and 350 GeV are shown. The "Stat + syst" band shows the envelope of the fit variations with statistical uncertainties. The ratio of the nominal MC background values (dashed line) and data to the ABCD prediction is shown as a dashed line in the ratio plot. The MC background uncertainties are not shown for visual clarity.
Distributions of $m_{\ell\ell}$ in the $\mathrm{SR_{b+\textrm{j}/b}^{mm}}$ SR. Events are divided by the bin width. Simulated signal shapes for $Z'$ boson masses of 125, 200, and 350 GeV are shown. The "Stat + syst" band shows the envelope of the fit variations with statistical uncertainties. The ratio of the nominal MC background values (dashed line) and data to the ABCD prediction is shown as a dashed line in the ratio plot. The MC background uncertainties are not shown for visual clarity.
Data vs. the ABCD method background prediction for 2016 in $\mathrm{SR_{b}^{mm}}$. Events are divided by the bin width, hence fractional data counts. Error bars show statistical uncertainties of data. The blue band shows the propagated uncertainty of all individual fit variations in a given bin, which we consider to be uncorrelated. The lower panels show the ratio of the observed data to the background estimation.
A search for single production of a vector-like T quark with charge $2/3\,e$, in the decay channel with a top quark and a neutral scalar boson $\phi$ is presented. The $\phi$ boson can be a standard model Higgs boson or a new particle beyond the standard model. The top quark is identified in its leptonic decay, and the neutral boson decays into a bottom quark-antiquark pair. Final states with boosted topologies are considered and machine learning techniques are exploited for optimal classification. The analysis uses data collected by the CMS experiment in proton-proton collisions at a center-of-mass energy of $13~\mathrm{TeV}$, corresponding to an integrated luminosity of $138~\mathrm{fb}^{-1}$ recorded at the CERN LHC in 2016$-$2018. Limits at $95\%$ confidence levels are set on the product of the cross section and branching fraction for a T quark of small decay width. They are in the range between 15 and $0.15~\mathrm{fb}$, depending on T quark and $\phi$ boson masses. In the case of the decay channel with a top quark and a standard model Higgs boson, for most of the studied range the analysis provides limits which are better or comparable with previous searches performed in CMS.
Distribution of the mass of the AK8 jet selected as the $\phi$ boson candidate for data and simulated background events in the (TopT, XbbL) validation region for the muon channel. The distribution is shown before the final fit for signal extraction.
Distribution of the mass of the AK8 jet selected as the $\phi$ boson candidate for data and simulated background events in the (TopT, XbbL) validation region for the electron channel. The distribution is shown before the final fit for signal extraction.
Distribution of the mass of the AK8 jet selected as the $\phi$ boson candidate for data and simulated background events in the (TopL, XbbL) validation region for the muon channel. The distribution is shown before the final fit for signal extraction.
Inclusive cross-sections for top-quark pair production in association with charm quarks are measured with proton-proton collision data at a center-of-mass energy of 13 TeV corresponding to an integrated luminosity of 140 fb$^{-1}$, collected with the ATLAS experiment at the LHC between 2015 and 2018. The measurements are performed by requiring one or two charged leptons (electrons and muons), two $b$-tagged jets, and at least one additional jet in the final state. A custom flavor-tagging algorithm is employed for the simultaneous identification of $b$-jets and $c$-jets. In a fiducial phase space that replicates the acceptance of the ATLAS detector, the cross-sections for $t\bar{t}+ {\geq} 2c$ and $t\bar{t}+1c$ production are measured to be $1.28^{+0.27}_{-0.24}\;\text{pb}$ and $6.4^{+1.0}_{-0.9}\;\text{pb}$, respectively. The measurements are primarily limited by uncertainties in the modeling of inclusive $t\bar{t}$ and $t\bar{t}+b\bar{b}$ production, in the calibration of the flavor-tagging algorithm, and by data statistics. Cross-section predictions from various $t\bar{t}$ simulations are largely consistent with the measured cross-section values, though all underpredict the observed values by 0.5 to 2.0 standard deviations. In a phase-space volume without requirements on the $t\bar{t}$ decay products and the jet multiplicity, the cross-section ratios of $t\bar{t}+ {\geq} 2c$ and $t\bar{t}+1c$ to total $t\bar{t}+\text{jets}$ production are determined to be $(1.23 \pm 0.25) \%$ and $(8.8 \pm 1.3) \%$.
Measured cross-section values in the fiducial phase space and inclusive volume for the various $t\bar{t}+jets$ categories.
Post-fit agreement between data and MC prediction for $SR_{\mathrm{loose}}^{1\ell5j}$ signal region, which uses the invariant mass of the two geometrically closest c-tagged jets, $m_{\mathit{cc}}^{\mathrm{min}\Delta R}$, as an observable. The hatched uncertainty bands include all uncertainties and their correlations. The last bins contain overflow events. "Other Top" includes single-top-quark production and associated production of $t\bar{t}$ and single top quarks with bosons. "Non-Top" includes W+jets, Z+jets, and diboson processes.
Post-fit agreement between data and MC prediction for the $SR_{\mathrm{tight}}^{1\ell5j}$ signal region, which uses the invariant mass of the two geometrically closest jets tagged with c@11%, $m_{\mathit{cc}}^{\mathrm{min}\Delta R}$, as an observable. The hatched uncertainty bands include all uncertainties and their correlations. The last bins contain overflow events. "Other Top" includes single-top-quark production and associated production of $t\bar{t}$ and single top quarks with bosons. "Non-Top" includes W+jets, Z+jets, and diboson processes.
This paper presents a combination of searches for the nonresonant production of Higgs boson pairs (HH) in proton-proton collisions at a centre-of-mass energy of 13 TeV. The data set was collected by the CMS experiment at the LHC from 2016 to 2018 and corresponds to a total integrated luminosity of 138 fb$^{-1}$. The observed (expected) upper limit on the inclusive HH production cross section relative to the standard model (SM) prediction is found to be 3.5 (2.5). Assuming all other Higgs boson couplings are equal to their SM values, the Higgs boson trilinear self-coupling modifier $κ_λ=λ_3/λ_{3}^\text{SM}$ is constrained in the range $-$1.35 $\leq$$κ_λ$$\leq$ 6.37 at 95% confidence level. Similarly, for the coupling modifier $κ_{2\mathrm{V}}$, which governs the interaction between two vector bosons and two Higgs bosons, we have excluded $κ_{2\mathrm{V}}$ = 0 at more than 5 standard deviations for all values of $κ_λ$. At 95% confidence level assuming other couplings are equal to their SM values, $κ_{2\mathrm{V}}$ is constrained in the range 0.64 $\leq$ $κ_{2\mathrm{V}}$ $\leq$ 1.40. This work also studies HH production in several new physics scenarios, using the Higgs effective field theory (HEFT) framework. The HEFT framework is further exploited to study various ultraviolet complete models with an extended Higgs sector and set constraints on specific parameters. An extrapolation of the results to the integrated luminosity expected after the high-luminosity upgrade of the LHC is reported as well.
Values of the effective Lagrangian couplings for the Higgs Effective field theory benchmarks proposed in Ref. [33].
Values of the effective Lagrangian couplings for the Higgs Effective field theory benchmarks proposed in Ref. [34].
Summary of results for the HH analyses included in this combination. The second column is the observed (expected) 95$\%$ CL upper limit on the inclusive signal strength $r$. The third (fourth) column is the allowed 68$\%$ CL interval for the coupling modifier $\kappa_\lambda$ ($\kappa _{2V}$). The last column indicates whether the analysis is included in the results using the HEFT parametrisation.
The total cross section for Compton scattering off atomic electrons, $γ+e\rightarrowγ'+e'$, was measured using photons with energies between 6.5 and 11.1 GeV incident on a $^9$Be target as part of the PrimEx-eta experiment in Hall D at Jefferson Lab. This is the first measurement of this fundamental QED process within this energy range. The total uncertainties of the cross section, combining the statistical and systematic components in quadrature, averaged to 3.4% across all energy bins. This not only demonstrates the capability of this experimental setup to perform precision cross-section measurements at forward angles but also allows us to compare with state-of-the-art QED calculations.
$\gamma +e^- \rightarrow \gamma + e^-$ total cross section in bins of photon beam energy. The first uncertainties are statistical, and the second are systematic.