Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New physics in $\Delta \Gamma_d$   We analyze the possibility of having new physics effects in the decay rate
difference, $\Delta \Gamma_d$, of neutral $B_d$ mesons. Three different sources
of enhancement are considered, CKM unitarity violations, beyond standard model
effects in the tree-level dimension six operators $(\bar{d}p)(\bar{p}'b)$ with
$p,p'=u,c$; and large enhancements of the almost unconstrained operators
$(\bar{d}b)(\bar{\tau}\tau)$. We find that deviations of several hundred per
cent from the standard model prediction of $\Delta \Gamma_d$ are not excluded
by current experimental data.

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The categories of this paper are: cs
33
The categories of this paper are: plasm-ph
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The categories of this paper are: econ
12
The categories of this paper are: nucl-th
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The categories of this paper are: gr-qc
29
The categories of this paper are: funct-an
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The categories of this paper are: acc-phys
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The categories of this paper are: cond-mat
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The categories of this paper are: solv-int
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The categories of this paper are: bayes-an
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The categories of this paper are: comp-gas
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The categories of this paper are: adap-org
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The categories of this paper are: nucl-ex
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The categories of this paper are: nlin
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The categories of this paper are: math
32
The categories of this paper are: atom-ph