Controlling ρ width effects for a precise value of α in B→ρρ
It has been pointed out that the currently most precise determination of the weak phase ϕ2=α of the Cabibbo–Kobayashi–Maskawa (CKM) matrix achieved in B→ρρ decays is susceptible to a small correction at a level of (Γρ/mρ)2 due to an I=1 amplitude caused by the ρ width. Using Breit–Wigner distributio...
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doaj-4f0c962ab98147caad4b40fad713d34e2020-11-24T22:54:36ZengElsevierPhysics Letters B0370-26931873-24452017-03-01766C34535010.1016/j.physletb.2017.01.022Controlling ρ width effects for a precise value of α in B→ρρMichael Gronau0Jonathan L. Rosner1Physics Department, Technion, Haifa 32000, IsraelEnrico Fermi Institute and Department of Physics, University of Chicago, Chicago, IL 60637, USAIt has been pointed out that the currently most precise determination of the weak phase ϕ2=α of the Cabibbo–Kobayashi–Maskawa (CKM) matrix achieved in B→ρρ decays is susceptible to a small correction at a level of (Γρ/mρ)2 due to an I=1 amplitude caused by the ρ width. Using Breit–Wigner distributions for the two pairs of pions forming ρ mesons, we study the I=1 contribution to B→ρρ decay rates as function of the width and location of the ρ band. We find that in the absence of a particular enhancement of the I=1 amplitude reducing a single band to a width Γρ at SuperKEKB leads to results which are completely insensitive to the ρ width. If the I=1 amplitude is dynamically enhanced relative to the I=0,2 amplitude one could subject its contribution to a “magnifying glass” measurement using two separated ρ bands of width Γρ. Subtraction of the I=1 contribution from the measured decay rate would lead to a very precise determination of the I=0,2 amplitude needed for performing the isospin analysis.http://www.sciencedirect.com/science/article/pii/S0370269317300291 |
collection |
DOAJ |
language |
English |
format |
Article |
sources |
DOAJ |
author |
Michael Gronau Jonathan L. Rosner |
spellingShingle |
Michael Gronau Jonathan L. Rosner Controlling ρ width effects for a precise value of α in B→ρρ Physics Letters B |
author_facet |
Michael Gronau Jonathan L. Rosner |
author_sort |
Michael Gronau |
title |
Controlling ρ width effects for a precise value of α in B→ρρ |
title_short |
Controlling ρ width effects for a precise value of α in B→ρρ |
title_full |
Controlling ρ width effects for a precise value of α in B→ρρ |
title_fullStr |
Controlling ρ width effects for a precise value of α in B→ρρ |
title_full_unstemmed |
Controlling ρ width effects for a precise value of α in B→ρρ |
title_sort |
controlling ρ width effects for a precise value of α in b→ρρ |
publisher |
Elsevier |
series |
Physics Letters B |
issn |
0370-2693 1873-2445 |
publishDate |
2017-03-01 |
description |
It has been pointed out that the currently most precise determination of the weak phase ϕ2=α of the Cabibbo–Kobayashi–Maskawa (CKM) matrix achieved in B→ρρ decays is susceptible to a small correction at a level of (Γρ/mρ)2 due to an I=1 amplitude caused by the ρ width. Using Breit–Wigner distributions for the two pairs of pions forming ρ mesons, we study the I=1 contribution to B→ρρ decay rates as function of the width and location of the ρ band. We find that in the absence of a particular enhancement of the I=1 amplitude reducing a single band to a width Γρ at SuperKEKB leads to results which are completely insensitive to the ρ width. If the I=1 amplitude is dynamically enhanced relative to the I=0,2 amplitude one could subject its contribution to a “magnifying glass” measurement using two separated ρ bands of width Γρ. Subtraction of the I=1 contribution from the measured decay rate would lead to a very precise determination of the I=0,2 amplitude needed for performing the isospin analysis. |
url |
http://www.sciencedirect.com/science/article/pii/S0370269317300291 |
work_keys_str_mv |
AT michaelgronau controllingrwidtheffectsforaprecisevalueofainbrr AT jonathanlrosner controllingrwidtheffectsforaprecisevalueofainbrr |
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