<?xml version="1.0" encoding="UTF-8"?><?xml-stylesheet type="text/xsl" href="static/style.xsl"?><OAI-PMH xmlns="http://www.openarchives.org/OAI/2.0/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:schemaLocation="http://www.openarchives.org/OAI/2.0/ http://www.openarchives.org/OAI/2.0/OAI-PMH.xsd"><responseDate>2026-04-18T03:13:58Z</responseDate><request verb="GetRecord" identifier="oai:www.recercat.cat:2445/133269" metadataPrefix="marc">https://recercat.cat/oai/request</request><GetRecord><record><header><identifier>oai:recercat.cat:2445/133269</identifier><datestamp>2025-12-05T17:01:47Z</datestamp><setSpec>com_2072_1057</setSpec><setSpec>col_2072_478823</setSpec><setSpec>col_2072_478904</setSpec><setSpec>col_2072_478917</setSpec></header><metadata><record xmlns="http://www.loc.gov/MARC21/slim" xmlns:dcterms="http://purl.org/dc/terms/" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns:doc="http://www.lyncode.com/xoai" xsi:schemaLocation="http://www.loc.gov/MARC21/slim http://www.loc.gov/standards/marcxml/schema/MARC21slim.xsd">
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      <subfield code="a">Calvo Gómez, Míriam</subfield>
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      <subfield code="a">Camboni, Alessandro</subfield>
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      <subfield code="a">Comerma Montells, Albert</subfield>
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      <subfield code="a">Garrido Beltrán, Lluís</subfield>
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      <subfield code="a">Graciani Díaz, Ricardo</subfield>
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      <subfield code="a">Graugés Pous, Eugeni</subfield>
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      <subfield code="a">Oyanguren Campos, Arantza de</subfield>
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      <subfield code="a">Pérez-Calero Yzquierdo, Antonio</subfield>
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      <subfield code="a">Potterat, Cédric</subfield>
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      <subfield code="a">Rives Molina, Vicente José</subfield>
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      <subfield code="a">Ruiz, Hugo (Ruiz Pérez)</subfield>
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      <subfield code="a">Ruiz Valls, Pablo</subfield>
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      <subfield code="a">Vilasis-Cardona, Xavier</subfield>
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      <subfield code="a">LHCb Collaboration</subfield>
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      <subfield code="c">2019-05-16T11:01:28Z</subfield>
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      <subfield code="c">2019-05-16T11:01:28Z</subfield>
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      <subfield code="c">2013-11-01</subfield>
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      <subfield code="c">2019-05-16T11:01:28Z</subfield>
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      <subfield code="a">The result of a search for the decay B + c → B 0 s π + is presented, using the B 0 s → D − s π + and B 0 s → J / ψ ϕ channels. The analysis is based on a data sample of p p collisions collected with the LHCb detector, corresponding to an integrated luminosity of 1     fb − 1 taken at a center-of-mass energy of 7 TeV, and 2     fb − 1 taken at 8 TeV. The decay B + c → B 0 s π + is observed with significance in excess of 5 standard deviations independently in both decay channels. The measured product of the ratio of cross sections and branching fraction is [ σ ( B + c ) / σ ( B 0 s ) ] × B ( B + c → B 0 s π + ) = [ 2.37 ± 0.31   ( stat ) ± 0.11   ( syst ) + 0.17 − 0.13 ( τ B + c ) ] × 10 − 3 , in the pseudorapidity range 2 &lt; η ( B ) &lt; 5 , where the first uncertainty is statistical, the second is systematic, and the third is due to the uncertainty on the B + c lifetime. This is the first observation of a B meson decaying to another B meson via the weak interaction.</subfield>
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      <subfield code="a">Física de partícules</subfield>
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      <subfield code="a">Experiments</subfield>
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      <subfield code="a">Observation of the Decay B+c→B0sπ+</subfield>
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