{"id":4078,"date":"2009-09-15T15:07:34","date_gmt":"2009-09-15T15:07:34","guid":{"rendered":"http:\/\/scienceblogs.com\/principles\/2009\/09\/15\/stupid-technical-question-mass\/"},"modified":"2009-09-15T15:07:34","modified_gmt":"2009-09-15T15:07:34","slug":"stupid-technical-question-mass","status":"publish","type":"post","link":"http:\/\/chadorzel.com\/principles\/2009\/09\/15\/stupid-technical-question-mass\/","title":{"rendered":"Stupid Technical Question: &#8220;Mass Insertion&#8221;"},"content":{"rendered":"<p>In reading a <a href=\"http:\/\/prola.aps.org\/abstract\/RMP\/v63\/i2\/p313_1\">theoretical paper on electric dipole moments<\/a> (well, OK, skimming through it looking for numbers), I ran across several Feynman diagrams with an &#8220;X&#8221; on one of the particle arrows. The caption contains the presumably-intended-to-be-helpful note &#8220;The cross denotes a mass insertion.&#8221;<\/p>\n<p>I have no idea what that means, and neither does the local person I ask to help me interpret such things. None of the undergrad-level nuclear\/ particle texts we looked at contained an explanation, either. <\/p>\n<p>This almost certainly means that it is some subtle technical point that is vastly beyond the level of knowledge that I need for the thing I was working on. Not knowing things bugs me, though, so anybody who does know what it means, and can provide or point to an upper-level-undergrad level explanation, please leave me a comment.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In reading a theoretical paper on electric dipole moments (well, OK, skimming through it looking for numbers), I ran across several Feynman diagrams with an &#8220;X&#8221; on one of the particle arrows. The caption contains the presumably-intended-to-be-helpful note &#8220;The cross denotes a mass insertion.&#8221; I have no idea what that means, and neither does the&hellip; <a class=\"more-link\" href=\"http:\/\/chadorzel.com\/principles\/2009\/09\/15\/stupid-technical-question-mass\/\">Continue reading <span class=\"screen-reader-text\">Stupid Technical Question: &#8220;Mass Insertion&#8221;<\/span><\/a><\/p>\n","protected":false},"author":2,"featured_media":0,"comment_status":"open","ping_status":"1","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[7,138],"tags":[],"class_list":["post-4078","post","type-post","status-publish","format-standard","hentry","category-physics","category-theory","entry"],"_links":{"self":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/4078","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/comments?post=4078"}],"version-history":[{"count":0,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/posts\/4078\/revisions"}],"wp:attachment":[{"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/media?parent=4078"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/categories?post=4078"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/chadorzel.com\/principles\/wp-json\/wp\/v2\/tags?post=4078"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}