.. _sphx_glr_api_gallery_particle_electroweak:

Electroweak theory
---------------------

Renormalized QED annihilation, the Higgs symmetry-breaking mechanism,
and their unification into a single electroweak theory, from
:mod:`physicskit.particle.electroweak`.


.. raw:: html

  <div id='sg-tag-list' class='sphx-glr-tag-list'></div>


.. raw:: html

    <div class="sphx-glr-thumbnails">

.. thumbnail-parent-div-open

.. raw:: html

    <div class="sphx-glr-thumbcontainer" tooltip="Renormalized QED&#x27;s cleanest tree-level prediction is e^+e^-\to\mu^+\mu^-, whose differential cross section in the massless-fermion limit is">

.. only:: html

  .. image:: /api/gallery/particle/electroweak/images/thumb/sphx_glr_plot_01_qed_annihilation_thumb.png
    :alt:

  :doc:`/api/gallery/particle/electroweak/plot_01_qed_annihilation`

.. raw:: html

      <div class="sphx-glr-thumbnail-title">Tomonaga, Schwinger, Feynman, and Dyson: renormalized QED</div>
    </div>


.. raw:: html

    <div class="sphx-glr-thumbcontainer" tooltip="In 1964, three independent groups showed how a gauge symmetry can be spontaneously broken while still keeping the theory&#x27;s equations exactly symmetric -- the mechanism that gives the W and Z bosons their mass while leaving the photon massless. The classical, single-field toy version is a real scalar in the double-well potential V(\phi)=-a\phi^2+b\phi^4: the field must &quot;choose&quot; one of two degenerate minima \phi=\pm v, v=\sqrt{a/(2b)}. This example evolves higgs_field_rollover from a tiny perturbation near the unstable symmetric point, watches it settle into one of the two vacua, and shows that a mirrored initial perturbation settles into the other, degenerate vacuum -- spontaneous symmetry breaking captured directly.">

.. only:: html

  .. image:: /api/gallery/particle/electroweak/images/thumb/sphx_glr_plot_02_higgs_mechanism_thumb.png
    :alt:

  :doc:`/api/gallery/particle/electroweak/plot_02_higgs_mechanism`

.. raw:: html

      <div class="sphx-glr-thumbnail-title">Higgs, Brout-Englert, and Guralnik-Hagen-Kibble: symmetry breaking</div>
    </div>


.. raw:: html

    <div class="sphx-glr-thumbcontainer" tooltip="Glashow (1961), Weinberg (1967), and Salam (1968) showed that the electromagnetic and weak interactions are two faces of a single SU(2)\times U(1) gauge theory, spontaneously broken by the Higgs mechanism into the massless photon (electromagnetism) and the massive W^\pm,Z^0 bosons (the weak force) -- unifying two of nature&#x27;s four fundamental interactions. Gargamelle&#x27;s 1973 discovery of weak neutral currents, mediated by the previously unobserved Z^0, was the theory&#x27;s first direct experimental confirmation. This example puts the theory&#x27;s two already-modeled pieces side by side: qed_dsigma_domega_mumu, the electromagnetic sector reproduced at low energy, and higgs_vev, the symmetry-breaking scale that gives the W/Z their mass while leaving the photon massless -- exactly the two ingredients the unification joins.">

.. only:: html

  .. image:: /api/gallery/particle/electroweak/images/thumb/sphx_glr_plot_03_unification_thumb.png
    :alt:

  :doc:`/api/gallery/particle/electroweak/plot_03_unification`

.. raw:: html

      <div class="sphx-glr-thumbnail-title">Glashow, Weinberg, and Salam: electroweak unification</div>
    </div>


.. thumbnail-parent-div-close

.. raw:: html

    </div>


.. toctree::
   :hidden:

   /api/gallery/particle/electroweak/plot_01_qed_annihilation
   /api/gallery/particle/electroweak/plot_02_higgs_mechanism
   /api/gallery/particle/electroweak/plot_03_unification