Model independent search for new phenomena in $p\overline{p}$ collisions at $\sqrt{s}\mathbf{=}1.96\mathrm{TeV}$

We describe a model-independent search for physics beyond the standard model in lepton final states. We examine 117 final states using $1.1{\mathrm{fb}}^{-1}$ of $p\overline{p}$ collisions data at $\sqrt{s}=1.96\mathrm{TeV}$ collected with the D0 detector. We conclude that all observed discrepancies between data and model can be attributed to uncertainties in the standard model background modeling, and hence we do not see any evidence for physics beyond the standard model.

Figure 1

$e+\mathrm{\text{jets}}$ final state (a) electron $p_T$ histogram and (b) transverse mass $(e,{\mathrm{E̸}}_T)$ check histogram.

Figure 2

$\mu +\mathrm{\text{jets}}$ final state (a) ${\mathrm{E̸}}_T$ histogram and (b) transverse mass $(\mu ,{\mathrm{E̸}}_T)$ check histogram.

Figure 3

$ee$ final state (a) leading electron (with highest $p_T$) $p_T$ fit histogram and (b) invariant mass $(e,e)$ check histogram.

Figure 4

$\mu \mu$ final state (a) leading muon $p_T$ fit histogram and (b) invariant mass $(\mu ,\mu )$ check histogram.

Figure 5

$\mu e$ final state (a) electron $p_T$ fit histogram and (b) invariant mass $(\mu ,e)$ check histogram.

Figure 6

$e\tau$ final state (a) The $\Delta \varphi (e,{\mathrm{E̸}}_T)$ fit histogram and (b) invariant mass $(e,\tau )$ check histogram.

Figure 7

$\mu \tau$ final state (a) muon $p_T$ fit histogram and (b) invariant mass $(\mu ,\tau )$ check histogram.

Figure 8

Sensitivity to new physics test using the $t\overline{t}$ final state. (a) The $t\overline{t}$ MC is included, yielding only minor differences between data and SM background. The statistical agreement between the data and MC for the distribution shown on inset is nearly $2\sigma$. (b) The results of the entire analysis without the $t\overline{t}$ MC. In this case, sleuth passes the criterion of interest at 0.001 for this final state. The insets show the distribution beyond the $\sum _{}^{}{p}_T$ cutoff. “Other” refers to contributions too small to list, including $W+b\overline{b}\to e\nu b\overline{b}$ events, $W+c\overline{c}\to \ell \nu c\overline{c}$ events, $W+lp\to \ell \nu +lp$ events, and diboson events.

Figure 9

Distribution of discrepancies for the 117 final states relative to the SM in terms of standard deviations calculated in vista final state before accounting for the trials factors. The curve represents a Gaussian distribution centered at zero to guide the eye. The distribution is expected to obey Poisson statistics, which is the reason the distribution is narrower than the Gaussian.

Figure 10

(a) The distribution of the pseudorapidity of the second jet with respect to the center of the D0 detector in the $\mu +2\mathrm{\text{jets}}+{\mathrm{E̸}}_T$ channel. Other contains distributions too small to list individually, $W+b\overline{b}$, diboson, $t\overline{t}$, and $\mathrm{D}\mathrm{\text{−}}\mathrm{Y}+0lp$. (b) The $\Delta \varphi$ distribution between the ${\mu }^{+}$ and the ${\mathrm{E̸}}_T$ for the ${\mu }^{+}{\mu }^{-}+{\mathrm{E̸}}_T$ final state. Other contains distributions too small to list individually, diboson and $t\overline{t}$.

Figure 11

The $\sigma$ distribution for the 5543 vista comparisons before accounting for number of the trials. The curve represents a Gaussian distribution centered at zero to guide the eye. There are 116 distributions in the underflow bin with $\sigma \le -10$. This is expected as histograms with Kolmogorov-Smirnov probabilities $>0.99999$ are rounded to 1, and appear in the underflow bin.

Figure 12

The discrepant distributions in the $\mu +2\mathrm{\text{jets}}+{\mathrm{E̸}}_T$ exclusive final state. (a) The transverse mass distribution of the $W$ boson plus second jet, (b) the $\Delta \mathcal{R}$ between the muon and the second jet, (c) the invariant mass distribution of the $\mu +\mathrm{\text{second jet}}$, and (d) $\Delta \eta$ between the highest $p_T$ jet and the second jet. Other contains distributions too small to list individually, $W+b\overline{b}$, diboson, $t\overline{t}$, and $\mathrm{D}\mathrm{\text{−}}\mathrm{Y}+0lp$.

Figure 13

The discrepant distributions in the $\mu +1\mathrm{\text{jet}}+{\mathrm{E̸}}_T$ exclusive final state: (a) the $p_T$ of the $W$ boson, (b) the sum of the scalar values of $p_T$ of the $\mu$, jet, and ${\mathrm{E̸}}_T$, (c) the transverse mass of the $\mu$ and ${\mathrm{E̸}}_T$, (d) the $p_T$ of the $\mu$, and (e) the $\Delta \varphi$ between the muon and the jet. Other contains distributions too small to list individually, $W+b\overline{b}$, diboson, $t\overline{t}$, and $\mathrm{D}\mathrm{\text{−}}\mathrm{Y}+0lp$.

Figure 14

The discrepant histograms in the $e+2\mathrm{\text{jets}}+{\mathrm{E̸}}_T$ exclusive final state. (a) The $\Delta \eta$ between the two jets, (b) the transverse mass of the trailing jet and ${\mathrm{E̸}}_T$, and (c) the transverse mass distribution of the $W$ boson plus trailing jet. Other contains distributions too small to list individually, diboson, D-Y, and $t\overline{t}$.

Figure 15

The discrepant distributions in the $e+1\mathrm{\text{jet}}+{\mathrm{E̸}}_T$ exclusive final state. (a) The $\Delta \varphi$ between the $e$ and ${\mathrm{E̸}}_T$, (b) the $p_T$ of the electron, (c) the $p_T$ of the $W$ boson, and (d) the ${\mathrm{E̸}}_T$ distribution. Other contains distributions too small to list individually, diboson, D-Y, and $t\overline{t}$.

Figure 16

Check of most discrepant CDF plots from [9], ${\mu }^{\pm }{e}^{\pm }$. The inset shows the distribution above the $\Sigma p_T$ cut.

Figure 17

Check of most discrepant CDF plots from [9], ${\mu }^{\pm }{e}^{\pm }+{\mathrm{E̸}}_T$. The inset shows the distribution above the $\Sigma p_T$ cut.

Figure 18

Check of most discrepant CDF plots from [9], ${\ell }^{\pm }{\ell }^{\mp }{\ell }^{\prime }+{\mathrm{E̸}}_T$. The inset shows the distribution above the $\Sigma p_T$ cut.

Figure 19

Since there are no data events in the ${\mu }^{\pm }{e}^{\pm }+2\mathrm{\text{jets}}+{\mathrm{E̸}}_T$ final state, the distribution for ${\mu }^{\pm }{e}^{\mp }+2\mathrm{\text{jets}}+{\mathrm{E̸}}_T$ is shown. The inset shows the distribution above the $\Sigma p_T$ cut. Other contains the $Z\to \mu \mu$ and $W/Z+b\overline{b}$ distributions.

Figure 20

Distribution of final state sleuth probabilities converted into units of $\sigma$ before inclusion of the final-state trials factor.

Figure 21

sleuth plot for ${\ell }^{\pm }+{\tau }^{\mp }+{\mathrm{E̸}}_T$. The inset shows the distribution above the $\Sigma p_T$ cut. Other includes D-Y $ee+\mathrm{\text{jet}}$ events, D-Y $\mu \mu +\mathrm{\text{jet}}$ events, diboson events, and $t\overline{t}$ events.