Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Contact Interaction Explanation of HERA Events and $SU(3)_C\times
  SU(2)_L\times U(1)_Y$ Invariance   We reexamine the contact interaction hypothesis for excess high-$Q^2$ events
seen at HERA in $e^+ p \to e^+ X$ scattering. We consider the most general
structure of contact interactions insisting on $SU(3)_C\times SU(2)_L \times
U(1)_Y$ invariance. Apart from constraints for $e^+ e^- \to q\bar q$ ,
Drell-Yan and atomic parity violation experiments, we find stringent
constraints from neutrino deep inelastic data. A possible choice of contact
terms that escape present bounds is still possible, althought new data from
FERMILAB and LEP should further constrain such a possibility.

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The categories of this paper are: hep-th
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The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
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The categories of this paper are: alg-geom
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The categories of this paper are: eess
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The categories of this paper are: math-ph
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The categories of this paper are: quant-ph
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The categories of this paper are: gr-qc
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The categories of this paper are: econ
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The categories of this paper are: q-fin
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The categories of this paper are: dg-ga
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The categories of this paper are: stat
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The categories of this paper are: nucl-ex
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The categories of this paper are: cmp-lg
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The categories of this paper are: ao-sci
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The categories of this paper are: hep-lat