Why particle can decay into 2 photons instead of 1 photon?












1















I recently read an old physic news about higgs boson was observed to decay into 2 photons and I wondering why it won't decay into 1 single photon with the combine energy of 2 photons?










share|cite|improve this question



























    1















    I recently read an old physic news about higgs boson was observed to decay into 2 photons and I wondering why it won't decay into 1 single photon with the combine energy of 2 photons?










    share|cite|improve this question

























      1












      1








      1








      I recently read an old physic news about higgs boson was observed to decay into 2 photons and I wondering why it won't decay into 1 single photon with the combine energy of 2 photons?










      share|cite|improve this question














      I recently read an old physic news about higgs boson was observed to decay into 2 photons and I wondering why it won't decay into 1 single photon with the combine energy of 2 photons?







      photons higgs proton-decay






      share|cite|improve this question













      share|cite|improve this question











      share|cite|improve this question




      share|cite|improve this question










      asked 2 hours ago









      user6760user6760

      2,45111736




      2,45111736






















          2 Answers
          2






          active

          oldest

          votes


















          4














          The Higgs boson has spin $0$. A photon has spin $1$. The total angular momentum cannot change in the decay, so a Higgs boson cannot decay into a single photon, regardless of the energy. But the total angular momentum of two photons can be zero (if their spins are oriented in opposite directions), so this decay mode can conserve angular momentum.






          share|cite|improve this answer



















          • 1





            I just look up spin so spin can be negative

            – user6760
            1 hour ago



















          1














          No massive particle can decay into a single photon.



          In its rest frame, a particle with mass $M$ has momentum $p=0$. If it decayed to a single photon, conservation of energy would require the photon energy to be $E=Mc^2$, while conservation of momentum would require the photon to maintain $p=0$. However, photons obey $E=pc$ (which is the special case of $E^2 = (pc)^2 + (mc^2)^2$ for massless particles). It's not possible to satisfy all these constraints at once. Composite particles may emit single photons, but no massive particle may decay to a photon.






          share|cite|improve this answer























            Your Answer





            StackExchange.ifUsing("editor", function () {
            return StackExchange.using("mathjaxEditing", function () {
            StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
            StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
            });
            });
            }, "mathjax-editing");

            StackExchange.ready(function() {
            var channelOptions = {
            tags: "".split(" "),
            id: "151"
            };
            initTagRenderer("".split(" "), "".split(" "), channelOptions);

            StackExchange.using("externalEditor", function() {
            // Have to fire editor after snippets, if snippets enabled
            if (StackExchange.settings.snippets.snippetsEnabled) {
            StackExchange.using("snippets", function() {
            createEditor();
            });
            }
            else {
            createEditor();
            }
            });

            function createEditor() {
            StackExchange.prepareEditor({
            heartbeatType: 'answer',
            autoActivateHeartbeat: false,
            convertImagesToLinks: false,
            noModals: true,
            showLowRepImageUploadWarning: true,
            reputationToPostImages: null,
            bindNavPrevention: true,
            postfix: "",
            imageUploader: {
            brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
            contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
            allowUrls: true
            },
            noCode: true, onDemand: true,
            discardSelector: ".discard-answer"
            ,immediatelyShowMarkdownHelp:true
            });


            }
            });














            draft saved

            draft discarded


















            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f453657%2fwhy-particle-can-decay-into-2-photons-instead-of-1-photon%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown

























            2 Answers
            2






            active

            oldest

            votes








            2 Answers
            2






            active

            oldest

            votes









            active

            oldest

            votes






            active

            oldest

            votes









            4














            The Higgs boson has spin $0$. A photon has spin $1$. The total angular momentum cannot change in the decay, so a Higgs boson cannot decay into a single photon, regardless of the energy. But the total angular momentum of two photons can be zero (if their spins are oriented in opposite directions), so this decay mode can conserve angular momentum.






            share|cite|improve this answer



















            • 1





              I just look up spin so spin can be negative

              – user6760
              1 hour ago
















            4














            The Higgs boson has spin $0$. A photon has spin $1$. The total angular momentum cannot change in the decay, so a Higgs boson cannot decay into a single photon, regardless of the energy. But the total angular momentum of two photons can be zero (if their spins are oriented in opposite directions), so this decay mode can conserve angular momentum.






            share|cite|improve this answer



















            • 1





              I just look up spin so spin can be negative

              – user6760
              1 hour ago














            4












            4








            4







            The Higgs boson has spin $0$. A photon has spin $1$. The total angular momentum cannot change in the decay, so a Higgs boson cannot decay into a single photon, regardless of the energy. But the total angular momentum of two photons can be zero (if their spins are oriented in opposite directions), so this decay mode can conserve angular momentum.






            share|cite|improve this answer













            The Higgs boson has spin $0$. A photon has spin $1$. The total angular momentum cannot change in the decay, so a Higgs boson cannot decay into a single photon, regardless of the energy. But the total angular momentum of two photons can be zero (if their spins are oriented in opposite directions), so this decay mode can conserve angular momentum.







            share|cite|improve this answer












            share|cite|improve this answer



            share|cite|improve this answer










            answered 2 hours ago









            Dan YandDan Yand

            8,03211133




            8,03211133








            • 1





              I just look up spin so spin can be negative

              – user6760
              1 hour ago














            • 1





              I just look up spin so spin can be negative

              – user6760
              1 hour ago








            1




            1





            I just look up spin so spin can be negative

            – user6760
            1 hour ago





            I just look up spin so spin can be negative

            – user6760
            1 hour ago











            1














            No massive particle can decay into a single photon.



            In its rest frame, a particle with mass $M$ has momentum $p=0$. If it decayed to a single photon, conservation of energy would require the photon energy to be $E=Mc^2$, while conservation of momentum would require the photon to maintain $p=0$. However, photons obey $E=pc$ (which is the special case of $E^2 = (pc)^2 + (mc^2)^2$ for massless particles). It's not possible to satisfy all these constraints at once. Composite particles may emit single photons, but no massive particle may decay to a photon.






            share|cite|improve this answer




























              1














              No massive particle can decay into a single photon.



              In its rest frame, a particle with mass $M$ has momentum $p=0$. If it decayed to a single photon, conservation of energy would require the photon energy to be $E=Mc^2$, while conservation of momentum would require the photon to maintain $p=0$. However, photons obey $E=pc$ (which is the special case of $E^2 = (pc)^2 + (mc^2)^2$ for massless particles). It's not possible to satisfy all these constraints at once. Composite particles may emit single photons, but no massive particle may decay to a photon.






              share|cite|improve this answer


























                1












                1








                1







                No massive particle can decay into a single photon.



                In its rest frame, a particle with mass $M$ has momentum $p=0$. If it decayed to a single photon, conservation of energy would require the photon energy to be $E=Mc^2$, while conservation of momentum would require the photon to maintain $p=0$. However, photons obey $E=pc$ (which is the special case of $E^2 = (pc)^2 + (mc^2)^2$ for massless particles). It's not possible to satisfy all these constraints at once. Composite particles may emit single photons, but no massive particle may decay to a photon.






                share|cite|improve this answer













                No massive particle can decay into a single photon.



                In its rest frame, a particle with mass $M$ has momentum $p=0$. If it decayed to a single photon, conservation of energy would require the photon energy to be $E=Mc^2$, while conservation of momentum would require the photon to maintain $p=0$. However, photons obey $E=pc$ (which is the special case of $E^2 = (pc)^2 + (mc^2)^2$ for massless particles). It's not possible to satisfy all these constraints at once. Composite particles may emit single photons, but no massive particle may decay to a photon.







                share|cite|improve this answer












                share|cite|improve this answer



                share|cite|improve this answer










                answered 21 mins ago









                robrob

                39.7k971164




                39.7k971164






























                    draft saved

                    draft discarded




















































                    Thanks for contributing an answer to Physics Stack Exchange!


                    • Please be sure to answer the question. Provide details and share your research!

                    But avoid



                    • Asking for help, clarification, or responding to other answers.

                    • Making statements based on opinion; back them up with references or personal experience.


                    Use MathJax to format equations. MathJax reference.


                    To learn more, see our tips on writing great answers.




                    draft saved


                    draft discarded














                    StackExchange.ready(
                    function () {
                    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fphysics.stackexchange.com%2fquestions%2f453657%2fwhy-particle-can-decay-into-2-photons-instead-of-1-photon%23new-answer', 'question_page');
                    }
                    );

                    Post as a guest















                    Required, but never shown





















































                    Required, but never shown














                    Required, but never shown












                    Required, but never shown







                    Required, but never shown

































                    Required, but never shown














                    Required, but never shown












                    Required, but never shown







                    Required, but never shown







                    Popular posts from this blog

                    A CLEAN and SIMPLE way to add appendices to Table of Contents and bookmarks

                    Calculate evaluation metrics using cross_val_predict sklearn

                    Insert data from modal to MySQL (multiple modal on website)