<p>We study the semileptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub><mo stretchy="false">→</mo><msubsup><mi>D</mi><mi>s</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><mi>τ</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> as a promising probe for new physics (NP) beyond the standard model (SM). The extension of the SM is done through the introduction of four-fermion operators beyond the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>V</mi><mo>−</mo><mi>A</mi></math> structure with the corresponding Wilson coefficients characterizing their contribution. The constraints on these coefficients are obtained from recent experimental data. Form factors describing hadron transitions are calculated in our covariant quark model with infrared confinement. Theoretical predictions for the full set of observables in these channels are provided. We analyze possible NP effects to be tested in future experiments.</p>

JINR

M.A. Ivanov

India

J.N. Pandya

Italy

P. Santorelli

N.R. Soni

Vietnam

C.T. Tran

H.C. Tran

Vo Quoc Phong

Detailed analysis of possible new-physics effects in the semileptonic decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>s</mi></msub><mo stretchy="false">→</mo><msubsup><mi>D</mi><mi>s</mi><mrow><mo stretchy="false">(</mo><mo>*</mo><mo stretchy="false">)</mo></mrow></msubsup><mi>τ</mi><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math>

This paper presents a detailed description of a model-independent method for the direct measurement of the Υ(4$\textit{S}$) → $\textit{B}$ $\textit{B}$ and Υ(4$\textit{S}$) → $$ {B}^0{\overline{B}}^0 $$ production fractions at $\textit{B}$ factories. The method is based on counting single- and double-inclusive charmed meson production at the Υ(4$\textit{S}$) resonance, providing statistical tagging of $$ {B}^0{\overline{B}}^0 $$ and $\textit{B}$ $\textit{B}$ events. A feasibility study indicates that a precision comparable to the current world average can be achieved without making any underlying assumptions, as the calculations rely solely on event yields.

Russia

M. Yasaveev

P. Pakhlov

N. Peters

A. Mufazalova

A model independent method for measurement of $\textit{B}$ ± and $\textit{B}$ 0 meson production fractions at Υ(4$\textit{S}$)

The strongly-coupled 3-dimensional theory, holographically dual to black branes at fixed chemical potential $\textit{μ}$ and temperature $\textit{T}$ ≪ $\textit{μ}$ is considered in AdS Einstein-Maxwell theory. The retarded Green’s functions at frequency $\textit{ω}$ is calculated using holography in the regime $\textit{ω}$, $\textit{T}$ ≪ $\textit{μ}$ but otherwise arbitrary. When the transverse space has finite volume, there is a non-zero energy scale $\textit{E}$ , scaling as 1/$\textit{μ}$ for large $\textit{μ}$, below which quantum-gravitational corrections due to the fluctuations of the nearly-gapless Schwarzian modes become important. Such corrections to the retarded Green’s function are calculated at different relative values of $\textit{ω}$, $\textit{T}$, and $\textit{E}$ . The $\textit{ω}$ → 0 limit is used to define the shear viscosity $\textit{η}$. As the temperature is lowered below $\textit{μ}$, quantum corrections are found to increase the value of $\textit{η}$ with respect to its semiclassical value. The quantum-corrected result for $\textit{η}$ diverges as $$ \sqrt{{\mathrm{E}}_{\mathrm{gap}}/T} $$ at $\textit{T}$ ≪ $\textit{E}$ , in accord with corresponding results for the absorption cross section. The quantum result for the ratio $\textit{η}$/$\textit{s}$, where $\textit{s}$ is the entropy density, dips below the semiclassical limit of 1/4$\textit{π}$ when $\textit{E}$ ≪ $\textit{T}$ ≪ $\textit{μ}$, then turns back to increase towards lower temperatures, and finally diverges at temperatures much below $\textit{E}$ .

Greece

Alexandros Kanargias

France

Elias Kiritsis

United Kingdom

Sameer Murthy

Olga Papadoulaki

Achilleas Porfyriadis

Holographic shear correlators at low temperatures, and quantum $\textit{η}$/$\textit{s}$

We report on the first measurement of the Central Exclusive Production process in proton-proton collisions: $\textit{pp}$ → $\textit{ph}$ $\textit{h}$ $\textit{p}$ (where $\textit{h}$ = $\textit{π}$, $\textit{K}$, $\textit{p}$) at the center-of-mass energy $$\sqrt{s}=510$$ GeV with the STAR experiment at RHIC. At this energy, the process is dominated by a double Pomeron exchange mechanism. Hence, it provides a clean environment for investigating Pomeron interactions by measuring fully reconstructed final states involving only two hadrons and two forward scattered protons. The oppositely charged hadron pairs are measured within the central detector of STAR. The forward scattered protons are measured in the Roman Pot system allowing the verification of the event’s exclusivity. Differential fiducial cross sections within the STAR acceptance are presented as a function of the difference in the azimuthal angle between the outgoing protons. The invariant masses of the charged hadron pairs are measured up to approximately 3 GeV and the square of the four-momentum transfer ($\textit{t}$ and $\textit{t}$ ) of the two forward-scattered protons in the range 0.3 GeV < −$\textit{t}$ , −$\textit{t}$ < 1.6 GeV . The differential fiducial cross sections of the forward protons as a function of the |$\textit{t}$ + $\textit{t}$ | are also presented. All results for the $\textit{π}$ $\textit{π}$ pair are presented in three mass ranges. A comparison with GRANIITTI Monte Carlo predictions are also presented, where the spectra include continuum and resonant contributions. The observed spectra are consistent with double Pomeron exchange, including resonances seen in previous studies.

United States

B. Aboona

Czechia

J. Adam

Poland

L. Adamczyk

I. Aggarwal

M. Aggarwal

Z. Ahammed

A. Alshammri

E. Aschenauer

China

S. Aslam

J. Atchison

Chile

V. Bairathi

X. Bao

P. Barik

K. Barish

S. Behera

R. Bellwied

P. Bhagat

A. Bhasin

S. Bhatta

S. Bhosale

J. Bielcik

J. Bielcikova

J. Brandenburg

C. Broodo

X. Cai

H. Caines

M. Calderon de la Barca Sanchez

D. Cebra

J. Ceska

I. Chakaberia

P. Chaloupka

Y. Chang

Z. Chang

A. Chatterjee

D. Chen

J. Chen

L. Chen

Q. Chen

W. Chen

Z. Chen

J. Cheng

Y. Cheng

W. Christie

X. Chu

S. Corey

H. Crawford

Hungary

M. Csanad

G. Dale-Gau

A. Das

D. Souza Lemos

Germany

I. Deppner

A. Deshpande

A. Dhamija

A. Dimri

P. Dixit

X. Dong

J. Drachenberg

E. Duckworth

J. Dunlop

Egypt

Y. El-Feky

J. Engelage

G. Eppley

Japan

S. Esumi

O. Evdokimov

O. Eyser

B. Fan

Y. Fang

R. Fatemi

S. Fazio

H. Feng

Y. Feng

E. Finch

Y. Fisyak

F. Flor

B. Fu

C. Fu

T. Fu

C. Gagliardi

T. Galatyuk

 Gao

T. Gao

G. Garcia

F. Geurts

A. Gibson

A. Giri

K. Gopal

X. Gou

D. Grosnick

A. Gu

J. Gu

A. Gupta

W. Guryn

A. Hamed

R. Hamilton

J. Han

X. Han

S. Harabasz

M. Harasty

J. Harris

H. Harrison-Smith

Study of Central Exclusive Production of $\textit{π}$ + $\textit{π}$ $\textit{−}$ , $\textit{K}$ + $\textit{K}$ $\textit{−}$ and $$p\overline{p }$$ pairs in proton-proton collisions at $$\sqrt{s}=510$$ GeV with the STAR detector at RHIC

A search is presented for emerging jets using $$140~\textrm{fb}^{-1}$$ of proton–proton collision data at $$\sqrt{s} = 13~\textrm{TeV}$$ , collected by the ATLAS experiment between 2015 and 2018. The search looks for the existence of a dark sector with symmetries similar to those in quantum chromodynamics. This dark sector is populated with dark quarks, which undergo showering similar to quarks in the Standard Model, leading to a high multiplicity of long-lived dark hadrons within a dark jet. These dark hadrons subsequently decay to Standard Model particles via a new heavy scalar mediating particle $$\phi $$ . This results in jets which contain multiple displaced vertices, known as emerging jets. This analysis targets four-jet topologies, with two emerging jets and two Standard Model jets, resulting from the decay of pair-produced scalar mediators. No significant excess above the Standard Model background is observed. For dark pion proper decay lengths of $$20~\textrm{mm}$$ , mediator masses are excluded between 1 and $$2~\textrm{TeV}$$ assuming a dark pion mass of $$20~\textrm{GeV}$$ .

G. Aad

Norway

E. Aakvaag

B. Abbott

United Arab Emirates

S. Abdelhameed

K. Abeling

N. Abicht

S. Abidi

M. Aboelela

Morocco

A. Aboulhorma

Israel

H. Abramowicz

Y. Abulaiti

B. Acharya

A. Ackermann

C. Bourdarios

S. Addepalli

M. Addison

J. Adelman

Türkiye

A. Adiguzel

T. Adye

A. Affolder

Y. Afik

Spain

M. Agaras

A. Aggarwal

Romania

C. Agheorghiesei

Azerbaijan

F. Ahmadov

S. Ahuja

X. Ai

G. Aielli

A. Aikot

M. Tamlihat

B. Aitbenchikh

Sweden

T. Åkesson

A. Akimov

D. Akiyama

N. Akolkar

S. Aktas

G. Alberghi

Canada

J. Albert

Switzerland

U. Alberti

P. Albicocco

G. Albouy

S. Alderweireldt

Z. Alegria

M. Aleksa

I. Aleksandrov

C. Alexa

T. Alexopoulos

F. Alfonsi

Search for emerging jets in $\textit{pp}$ collisions at $$\sqrt{s} = 13~\textrm{TeV}$$ with the ATLAS experiment