The LHCb measurement of the lifetime ratio of the an id="mmlsi1" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si1.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=c655beeaa08faa060a8ca257c266baec">ass="imgLazyJSB inlineImage" height="18" width="18" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si1.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si1.gif" overflow="scroll">螞b0ath>an>an>an> baryon to the an id="mmlsi2" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si2.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=0b99828119809b542144111ec9de7def">ass="imgLazyJSB inlineImage" height="13" width="17" alt="View the MathML source" style="margin-top: -5px; vertical-align: middle" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si2.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si2.gif" overflow="scroll">accent="true">B¯0ath>an>an>an> meson is updated using data corresponding to an integrated luminosity of 3.0 fb−1 collected using 7 and 8 TeV centre-of-mass energy pp collisions at the LHC. The decay modes used are an id="mmlsi3" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si3.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=515550d5adde13167d04f6c263e0c4af">ass="imgLazyJSB inlineImage" height="19" width="95" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si3.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si3.gif" overflow="scroll">螞b0alse">→Jalse">/蠄pK−ath>an>an>an> and an id="mmlsi4" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si4.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=6dc3e442a3f9f72cc5d3e5d90e3654f8">ass="imgLazyJSB inlineImage" height="16" width="105" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si4.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si4.gif" overflow="scroll">accent="true">B¯0alse">→Jalse">/蠄蟺+K−ath>an>an>an>, where the an id="mmlsi5" class="mathmlsrc">an class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si5.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=89c7826734d7f34be743c0c9ba60b77f" title="Click to view the MathML source">蟺+K−an>an class="mathContainer hidden">an class="mathCode">ath altimg="si5.gif" overflow="scroll">蟺+K−ath>an>an>an> mass is consistent with that of the an id="mmlsi6" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si6.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=b7019f307afce4a1e0490ab94ea60f9e">ass="imgLazyJSB inlineImage" height="16" width="56" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si6.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si6.gif" overflow="scroll">accent="true">K¯鈦?/mo>0alse">(892alse">)ath>an>an>an> meson. The lifetime ratio is determined with unprecedented precision to be an id="mmlsi7" class="mathmlsrc">an class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si7.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=da8b6de480debaa5ad305b97c2a38f5a" title="Click to view the MathML source">0.974±0.006±0.004an>an class="mathContainer hidden">an class="mathCode">ath altimg="si7.gif" overflow="scroll">0.974±0.006±0.004ath>an>an>an>, where the first uncertainty is statistical and the second systematic. This result is in agreement with original theoretical predictions based on the heavy quark expansion. Using the current world average of the an id="mmlsi2" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si2.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=0b99828119809b542144111ec9de7def">ass="imgLazyJSB inlineImage" height="13" width="17" alt="View the MathML source" style="margin-top: -5px; vertical-align: middle" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si2.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si2.gif" overflow="scroll">accent="true">B¯0ath>an>an>an> lifetime, the an id="mmlsi8" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si8.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=678caf5a6a9e0f8ff22af32a6434d5a0">ass="imgLazyJSB inlineImage" height="18" width="18" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269314003232-si8.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si8.gif" overflow="scroll">螞b0ath>an>an>an> lifetime is found to be an id="mmlsi9" class="mathmlsrc">an class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269314003232&_mathId=si9.gif&_user=111111111&_pii=S0370269314003232&_rdoc=1&_issn=03702693&md5=1c51ed31fa23cfe35bda39b1676bd89b" title="Click to view the MathML source">1.479±0.009±0.010 psan>an class="mathContainer hidden">an class="mathCode">ath altimg="si9.gif" overflow="scroll">1.479±0.009±0.010psath>an>an>an>.