Using a data set corresponding to an integrated luminosity of an id="mmlsi2" class="mathmlsrc">an class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269316305779&_mathId=si2.gif&_user=111111111&_pii=S0370269316305779&_rdoc=1&_issn=03702693&md5=d3ed4e2b5b9f6fb7dd8b454ad4020fac" title="Click to view the MathML source">3 fb−1an>an class="mathContainer hidden">an class="mathCode">ath altimg="si2.gif" overflow="scroll">3 fb−1ath>an>an>an>, collected by the LHCb experiment in pp collisions at centre-of-mass energies of 7 and 8 TeV, the effective lifetime in 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-S0370269316305779&_mathId=si1.gif&_user=111111111&_pii=S0370269316305779&_rdoc=1&_issn=03702693&md5=eb9fe7373a0fa2f9e69955ed5d96d05a">ass="imgLazyJSB inlineImage" height="17" width="74" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305779-si1.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si1.gif" overflow="scroll">Bs0alse">→Jalse">/ψηath>an>an>an> decay mode, an id="mmlsi33" class="mathmlsrc">an class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269316305779&_mathId=si33.gif&_user=111111111&_pii=S0370269316305779&_rdoc=1&_issn=03702693&md5=c67dfc02f6b4d1cad40d5fa82c18f0a7" title="Click to view the MathML source">τeffan>an class="mathContainer hidden">an class="mathCode">ath altimg="si33.gif" overflow="scroll">τathvariant="normal">effath>an>an>an>, is measured to be
Assuming CP conservation, an id="mmlsi33" class="mathmlsrc">an class="formulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269316305779&_mathId=si33.gif&_user=111111111&_pii=S0370269316305779&_rdoc=1&_issn=03702693&md5=c67dfc02f6b4d1cad40d5fa82c18f0a7" title="Click to view the MathML source">τeffan>an class="mathContainer hidden">an class="mathCode">ath altimg="si33.gif" overflow="scroll">τathvariant="normal">effath>an>an>an> corresponds to the lifetime of the light an id="mmlsi105" class="mathmlsrc"><a title="View the MathML source" class="mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269316305779&_mathId=si105.gif&_user=111111111&_pii=S0370269316305779&_rdoc=1&_issn=03702693&md5=2e683e6a7f29bd499403821400614d11">ass="imgLazyJSB inlineImage" height="17" width="17" alt="View the MathML source" title="View the MathML source" src="/sd/grey_pxl.gif" data-inlimgeid="1-s2.0-S0370269316305779-si105.gif">a>an class="mathContainer hidden">an class="mathCode">ath altimg="si105.gif" overflow="scroll">Bs0ath>an>an>an> mass eigenstate. This is the first measurement of the effective lifetime in this decay mode.