By analyzing a data set of mmlsi1" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si1.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=5ac9b219e4d7add8e514615925064c2a" title="Click to view the MathML source">2.92 fb−1mathContainer hidden">mathCode"><math altimg="si1.gif" overflow="scroll"><mn>2.92mn><mtext> mtext><msup><mrow><mtext>fbmtext>mrow><mrow><mo>−mo><mn>1mn>mrow>msup>math> of mmlsi2" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si2.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=fb3d2a9441c1aa328f53564f73e41df8" title="Click to view the MathML source">e+e−mathContainer hidden">mathCode"><math altimg="si2.gif" overflow="scroll"><msup><mrow><mi>emi>mrow><mrow><mo>+mo>mrow>msup><msup><mrow><mi>emi>mrow><mrow><mo>−mo>mrow>msup>math> collision data taken at mmlsi3" class="mathmlsrc">mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si3.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=b8b0c7711ae5e10bae05a5e18d229680">mg class="imgLazyJSB inlineImage" height="15" width="100" 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-S0370269315009302-si3.gif">mathContainer hidden">mathCode"><math altimg="si3.gif" overflow="scroll"><msqrt><mi>smi>msqrt><mo>=mo><mn>3.773mn><mtext> mtext><mtext>GeVmtext>math> and mmlsi26" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si26.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=33052b5567982ada8b233dfcea4e59c5" title="Click to view the MathML source">106.41×106mathContainer hidden">mathCode"><math altimg="si26.gif" overflow="scroll"><mn>106.41mn><mo>×mo><msup><mrow><mn>10mn>mrow><mrow><mn>6mn>mrow>msup>math>mmlsi5" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si5.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=5a737de914a3a12232a8863a77a856dd" title="Click to view the MathML source">ψ(3686)mathContainer hidden">mathCode"><math altimg="si5.gif" overflow="scroll"><mi>ψmi><mo stretchy="false">(mo><mn>3686mn><mo stretchy="false">)mo>math> decays taken at mmlsi146" class="mathmlsrc">mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si146.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=1d9c01a22b23cdb402dbcf6d4e9df5a2">mg class="imgLazyJSB inlineImage" height="15" width="100" 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-S0370269315009302-si146.gif">mathContainer hidden">mathCode"><math altimg="si146.gif" overflow="scroll"><msqrt><mi>smi>msqrt><mo>=mo><mn>3.686mn><mtext> mtext><mtext>GeVmtext>math> with the BESIII detector at the BEPCII collider, we measure the branching fraction and the partial decay width for mmlsi20" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si20.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=b20695fcc06bcb02ae597a62735b142a" title="Click to view the MathML source">ψ(3770)→γχc0mathContainer hidden">mathCode"><math altimg="si20.gif" overflow="scroll"><mi>ψmi><mo stretchy="false">(mo><mn>3770mn><mo stretchy="false">)mo><mo stretchy="false">→mo><mi>γmi><msub><mrow><mi>χmi>mrow><mrow><mi>cmi><mn>0mn>mrow>msub>math> to be mmlsi147" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si147.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=715ac6dc320e7f1874c6d9f23c053001" title="Click to view the MathML source">B(ψ(3770)→γχc0)=(6.88±0.28±0.67)×10−3mathContainer hidden">mathCode"><math altimg="si147.gif" overflow="scroll"><mi mathvariant="script">Bmi><mo stretchy="false">(mo><mi>ψmi><mo stretchy="false">(mo><mn>3770mn><mo stretchy="false">)mo><mo stretchy="false">→mo><mi>γmi><msub><mrow><mi>χmi>mrow><mrow><mi>cmi><mn>0mn>mrow>msub><mo stretchy="false">)mo><mo>=mo><mo stretchy="false">(mo><mn>6.88mn><mo>±mo><mn>0.28mn><mo>±mo><mn>0.67mn><mo stretchy="false">)mo><mo>×mo><msup><mrow><mn>10mn>mrow><mrow><mo>−mo><mn>3mn>mrow>msup>math> and mmlsi148" class="mathmlsrc">mulatext stixSupport mathImg" data-mathURL="/science?_ob=MathURL&_method=retrieve&_eid=1-s2.0-S0370269315009302&_mathId=si148.gif&_user=111111111&_pii=S0370269315009302&_rdoc=1&_issn=03702693&md5=b95705661e07bd3314a9c50d81044b08" title="Click to view the MathML source">Γ[ψ(3770)→γχc0]=(187±8±19) keVmathContainer hidden">mathCode"><math altimg="si148.gif" overflow="scroll"><mi mathvariant="normal">Γmi><mo stretchy="false">[mo><mi>ψmi><mo stretchy="false">(mo><mn>3770mn><mo stretchy="false">)mo><mo stretchy="false">→mo><mi>γmi><msub><mrow><mi>χmi>mrow><mrow><mi>cmi><mn>0mn>mrow>msub><mo stretchy="false">]mo><mo>=mo><mo stretchy="false">(mo><mn>187mn><mo>±mo><mn>8mn><mo>±mo><mn>19mn><mo stretchy="false">)mo><mtext> mtext><mtext>keVmtext>math>, respectively. These are the most precise measurements to date.