We study the melting of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> pairs in the early stage of high-energy proton-nucleus collisions. We describe the early stage in terms of an evolving <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><mo stretchy="false">)</mo></math> glasma stage, that is dominated by intense, out-of-equilibrium gluon fields. On top of these fields, we liberate heavy quark-antiquark pairs, whose constituents are let evolve according to relativistic kinetic theory coupled to the gluon fields. We define a pair-by-pair probability that the pair melts during the evolution, which we relate to the fluctuations of the color charges induced by the interaction of the quarks with the gluon fields. We find that color decorrelation is the main melting mechanism within the pre-equilibrium stage. Moreover, we estimate that within <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Δ</mi><mi>τ</mi><mo>≈</mo><mn>0.4</mn><mi>–</mi><mn>0.5</mn><mtext> </mtext><mtext> </mtext><mi>fm</mi><mo>/</mo><mi mathvariant="normal">c</mi></mrow></math> after the formation time of the pairs, about 50% of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> pairs are melted.

Italy

Lucia Oliva

Gabriele Parisi

Vincenzo Greco

Marco Ruggieri

Melting of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi><mover accent="true"><mi>c</mi><mo stretchy="false">¯</mo></mover></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi><mover accent="true"><mi>b</mi><mo stretchy="false">¯</mo></mover></math> pairs in the pre-equilibrium stage of proton-nucleus collisions at the Large Hadron Collider

In this work, nontrivial analytic structure of the quark propagator is discussed for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>B</mi></mrow></math>-meson inclusive decays. Attributed to invalidity of the standard Källén-Lehman spectral representation, complex conjugate poles alter the evaluation of decay rates, which lead to violation of quark-hadron duality. As phenomenological observables, widths in <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>X</mi><mi>c</mi></msub><mo>ℓ</mo><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> decay as well as the lifetime of the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>d</mi><mn>0</mn></msubsup></math> meson are discussed. In the presence of the mentioned nonanalytical contributions, the possibility for resolving the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>c</mi><mi>b</mi></mrow></msub><mo stretchy="false">|</mo></math> puzzle is addressed. It is demonstrated that there exists a parameter region, which explains <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">|</mo><msub><mi>V</mi><mrow><mi>c</mi><mi>b</mi></mrow></msub><mo stretchy="false">|</mo></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>d</mi><mn>0</mn></msubsup></math>-meson lifetime simultaneously within <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mn>1</mn><mi>σ</mi></mrow></math> via the complex conjugate poles from a charm quark.

China

Jinglong Zhu

Hiroyuki Umeeda

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>B</mi><mo stretchy="false">→</mo><msub><mi>X</mi><mi>c</mi></msub><mo>ℓ</mo><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover></math> decay as a probe of complex conjugate poles

Is the standard model charge-parity (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math>) violation ever enough to generate the observed baryon asymmetry? Yes! We introduce a mechanism of baryogenesis (and dark matter production) that can generate the entire observed baryon asymmetry of the Universe using only the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation within standard model systems—a feat which no other mechanism currently proposed can achieve. Baryogenesis proceeds through a mesogenesis scenario but with well motivated additional dark sector dynamics: a morphon field generates present day mass contributions for the particle mediating the decay responsible for baryogenesis. The effect is an enhancement of baryon production while evading present day collider constraints. The <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation comes entirely from standard model contributions to neutral meson systems. Meanwhile, the dark dynamics generate gravitational waves that may be searched for with current and upcoming pulsar timing arrays, as we demonstrate with an example potential that is tuned to generate domain walls that annihilate later. This mechanism, mesogenesis with a morphing mediator, motivates probing a new parameter space as well as improving the sensitivity of existing mesogenesis searches at hadron and electron colliders.

United States

Gilly Elor

CERN

Rachel Houtz

Canada

Seyda Ipek

Martha Ulloa

Standard model <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation is enough

We discuss prompt production of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> mesons in proton-proton collisions at the <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mrow><mn>68.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></mrow></math> energy within the nonrelativistic quantum chromodynamics <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math>-factorization approach using different unintegrated gluon distribution functions (UGDFs). We include both direct color-singlet production (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>g</mi><mi>g</mi><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>g</mi></math>) as well as a feed-down from <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>γ</mi></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ψ</mi><mo>′</mo></msup><mo stretchy="false">→</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mi>X</mi></math> decays. The production of the decaying mesons <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ψ</mi><mo>′</mo></msup></math> is also calculated within the nonrelativistic quantum chromodynamics <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math>-factorization approach. Differential distributions in the rapidity and transverse momentum of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math> are calculated and compared with experimental data of LHCb collaboration. The LHCb fixed target data allow us to test UGDFs in a new range of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>x</mi></math>.

Poland

Anna Cisek

Antoni Szczurek

Prompt inclusive production of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msup><mi>ψ</mi><mo>′</mo></msup></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>χ</mi><mi>c</mi></msub></math> mesons at <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msqrt><mi>s</mi></msqrt><mo>=</mo><mn>68.5</mn><mtext> </mtext><mtext> </mtext><mi>GeV</mi></math> energy within the NRQCD <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>k</mi><mi>t</mi></msub></math>-factorization approach

In this article, the vector, axial vector, and tensor form factors of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub></math> (<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>=</mo><mn>0</mn></math>, 1, 2) and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub><mo stretchy="false">→</mo><msub><mi>h</mi><mi>c</mi></msub></math> are analyzed within the framework of three-point QCD sum rules. With the calculated vector and axial vector form factors, we directly study the decay widths and branching ratios of semileptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>−</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><mi>l</mi><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>l</mi></msub><mo>,</mo><msub><mi>h</mi><mi>c</mi></msub><mi>l</mi><msub><mover accent="true"><mi>ν</mi><mo stretchy="false">¯</mo></mover><mi>l</mi></msub></math> <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mi>l</mi><mo>=</mo><mi>e</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>τ</mi></math>) and analyze the nonleptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>−</mo></msubsup><mo stretchy="false">→</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><msup><mi>π</mi><mo>−</mo></msup><mo>,</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><msup><mi>K</mi><mo>−</mo></msup><mo>,</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><msup><mi>ρ</mi><mo>−</mo></msup><mo>,</mo><msub><mi>χ</mi><mrow><mi>c</mi><mi>J</mi></mrow></msub><msup><mi>K</mi><mrow><mo>*</mo><mo>−</mo></mrow></msup></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>−</mo></msubsup><mo stretchy="false">→</mo><msub><mi>h</mi><mi>c</mi></msub><msup><mi>π</mi><mo>−</mo></msup><mo>,</mo><msub><mi>h</mi><mi>c</mi></msub><msup><mi>K</mi><mo>−</mo></msup><mo>,</mo><msub><mi>h</mi><mi>c</mi></msub><msup><mi>ρ</mi><mo>−</mo></msup><mo>,</mo><msub><mi>h</mi><mi>c</mi></msub><msup><mi>K</mi><mrow><mo>*</mo><mo>−</mo></mrow></msup></math> by using the naive factorization approach. These results can provide more information to understand the properties of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub></math> meson and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math>-wave charmonia and to study the heavy quark dynamics.

Jie Lu

Dian-Yong Chen

Guo-Liang Yu

Zhi-Gang Wang

Bin Wu

Systematic analysis of the form factors of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub></math> to <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>P</mi></math>-wave charmonia and corresponding weak decays

Based on <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo stretchy="false">(</mo><mn>2712.4</mn><mo>±</mo><mn>14.3</mn><mo stretchy="false">)</mo><mo>×</mo><msup><mn>10</mn><mn>6</mn></msup><mtext> </mtext><mtext> </mtext><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo></math> events collected by the BESIII detector operating at the BEPCII storage ring, we perform a search for the baryon- and lepton-number violating decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>p</mi><msup><mi>e</mi><mo>−</mo></msup><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></math> via <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>ψ</mi><mo stretchy="false">(</mo><mn>3686</mn><mo stretchy="false">)</mo><mo stretchy="false">→</mo><msup><mi>π</mi><mo>+</mo></msup><msup><mi>π</mi><mo>−</mo></msup><mi>J</mi><mo>/</mo><mi>ψ</mi></math>. No significant signal is found. An upper limit on the branching fraction of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>p</mi><msup><mi>e</mi><mo>−</mo></msup><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo><mo stretchy="false">)</mo></math> is found to be <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mn>3.1</mn><mo>×</mo><msup><mn>10</mn><mrow><mo>−</mo><mn>8</mn></mrow></msup></math> at 90% confidence level.

M. Ablikim

Russia

M.N. Achasov

Sweden

P. Adlarson

X.C. Ai

Germany

R. Aliberti

A. Amoroso

Q. An

Y. Bai

JINR

O. Bakina

Y. Ban

H.R. Bao

V. Batozskaya

Mongolia

K. Begzsuren

N. Berger

M. Berlowski

M. Bertani

D. Bettoni

F. Bianchi

E. Bianco

A. Bortone

I. Boyko

R.A. Briere

A. Brueggemann

H. Cai

M.H. Cai

X. Cai

A. Calcaterra

G.F. Cao

N. Cao

Türkiye

S.A. Cetin

X.Y. Chai

J.F. Chang

G.R. Che

Y.Z. Che

G. Chelkov

C. Chen

C.H. Chen

Chao Chen

G. Chen

H.S. Chen

H.Y. Chen

M.L. Chen

S.J. Chen

S.L. Chen

S.M. Chen

T. Chen

X.R. Chen

X.T. Chen

Y.B. Chen

Y.Q. Chen

Z.J. Chen

South Korea

S.K. Choi

X. Chu

G. Cibinetto

F. Cossio

J.J. Cui

H.L. Dai

J.P. Dai

A. Dbeyssi

R.E. de Boer

D. Dedovich

C.Q. Deng

Z.Y. Deng

A. Denig

I. Denysenko

M. Destefanis

F. De Mori

B. Ding

X.X. Ding

Y. Ding

Y.X. Ding

J. Dong

L.Y. Dong

M.Y. Dong

X. Dong

M.C. Du

S.X. Du

Y.Y. Duan

Z.H. Duan

P. Egorov

G.F. Fan

J.J. Fan

Y.H. Fan

J. Fang

S.S. Fang

W.X. Fang

Y.Q. Fang

R. Farinelli

L. Fava

F. Feldbauer

G. Felici

C.Q. Feng

J.H. Feng

Y.T. Feng

M. Fritsch

C.D. Fu

J.L. Fu

Y.W. Fu

Search for the baryon and lepton number violating decay <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi><mo stretchy="false">→</mo><mi>p</mi><msup><mi>e</mi><mo>−</mo></msup><mo>+</mo><mi mathvariant="normal">c</mi><mo>.</mo><mi mathvariant="normal">c</mi><mo>.</mo></math>

We present a lattice quantum chromodynamics (QCD) determination of the vector and axial-vector form factors that describe the charm-baryon semileptonic decays <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi mathvariant="normal">Ξ</mi><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math>. The calculation uses a domain-wall action for the up, down, and strange quarks, and an anisotropic clover action for the charm quark. We use four ensembles of gauge-field configurations generated by the RBC and UKQCD collaborations, with lattice spacings between 0.111 and 0.073 fm and pion masses ranging from 420 to 230 MeV. We present Standard Model predictions for the decay rates and branching fractions of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>−</mo></msubsup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mo>+</mo></msubsup><mo stretchy="false">→</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup><msup><mo>ℓ</mo><mo>+</mo></msup><msub><mi>ν</mi><mo>ℓ</mo></msub></math> for <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mo>ℓ</mo><mo>=</mo><mi>e</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi>μ</mi></mrow></math>. In particular, we obtain <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mrow><mi mathvariant="normal">Γ</mi><mo stretchy="false">(</mo><msubsup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mi>c</mi></mrow><mrow><mn>0</mn></mrow></msubsup><mo stretchy="false">→</mo><msup><mrow><mi mathvariant="normal">Ξ</mi></mrow><mrow><mo>−</mo></mrow></msup><msup><mrow><mi>e</mi></mrow><mrow><mo>+</mo></mrow></msup><msub><mrow><mi>ν</mi></mrow><mrow><mi>e</mi></mrow></msub><mo stretchy="false">)</mo><mo>/</mo><mo stretchy="false">|</mo><msub><mrow><mi>V</mi></mrow><mrow><mi>c</mi><mi>s</mi></mrow></msub><msup><mrow><mo stretchy="false">|</mo></mrow><mrow><mn>2</mn></mrow></msup><mo>=</mo><mn>0.2515</mn><mo stretchy="false">(</mo><mn>73</mn><mo stretchy="false">)</mo><mtext> </mtext><mtext> </mtext><msup><mrow><mi>ps</mi></mrow><mrow><mo>−</mo><mn>1</mn></mrow></msup></mrow></math> and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="script">B</mi><mo stretchy="false">(</mo><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup><mo stretchy="false">→</mo><msup><mi mathvariant="normal">Ξ</mi><mo>−</mo></msup><msup><mi>e</mi><mo>+</mo></msup><msub><mi>ν</mi><mi>e</mi></msub><mo stretchy="false">)</mo><mo>=</mo><mn>3.58</mn><mo stretchy="false">(</mo><mn>12</mn><mo stretchy="false">)</mo><mo>%</mo></math>. These values are higher than those predicted by a previous lattice calculation and substantially higher than the experimentally measured values, but consistent with expectations from approximate <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>S</mi><mi>U</mi><mo stretchy="false">(</mo><mn>3</mn><mo stretchy="false">)</mo></math> flavor symmetry.

Callum Farrell

Stefan Meinel

<math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi mathvariant="normal">Ξ</mi><mi>c</mi></msub><mo stretchy="false">→</mo><mi mathvariant="normal">Ξ</mi></math> form factors from lattice QCD with domain-wall quarks: A new piece in the puzzle of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi mathvariant="normal">Ξ</mi><mi>c</mi><mn>0</mn></msubsup></math> decay rates

In this Letter, we demonstrate that <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-odd and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-even correlations, with <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math> representing time reversal, when satisfying specific conditions, result, respectively, in cosine and sine strong phase dependencies of the corresponding <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation. Additionally, we identify pairs of these <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation observables in hadron decays depend on precisely the same strong phases within the helicity amplitude scheme. This complementarity could reduce the strong phase reliance in the study of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation while also mitigating the risk of suppressed <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation due to exceptionally small strong phases. Moreover, our proposal holds broad application prospects in further investigating <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation in baryon decays, which has recently been discovered in the LHCb experiment.

Jian-Peng Wang

Qin Qin

Fu-Sheng Yu

Complementary <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>C</mi><mi>P</mi></math> violation induced by <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-odd and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>T</mi></math>-even correlations

The valence quark parton distribution functions (PDFs) of all ground state heavy mesons composed of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi></math> quarks, are discussed; namely, the pseudoscalar <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>c</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>η</mi><mi>b</mi></msub><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msub><mi>B</mi><mi>c</mi></msub></math>, together with the corresponding vector ones, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>J</mi><mo>/</mo><mi>ψ</mi></math>, <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi mathvariant="normal">ϒ</mi><mo stretchy="false">(</mo><mn>1</mn><mi>S</mi><mo stretchy="false">)</mo></math>, and <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><msubsup><mi>B</mi><mi>c</mi><mo>*</mo></msubsup></math>. We use a quantum chromodynamics (QCD)-inspired constituent quark model, which has been applied with success to conventional heavy mesons, so that one advantage here is that all parameters have already been fixed by previous studies. The wave functions of the heavy mesons in the rest frame are obtained by solving the Schrödinger equation, then boosted to its light-front, based on Susskind’s Lorentz transformation. The PDFs at the hadron scale, are then obtained by integrating out the transverse momenta of the modulus square of the light-front wave function. Our study shows how the valence quark distributions differ between pseudoscalar and vector mesons, as well as among charmonia, bottomonia and bottom-charmed mesons. Comparisons with other theoretical calculations demonstrate that the PDFs obtained herein are in general narrower but align well with the expected patterns. Moreover, each PDF’s pointwise behavior is squeezed with respect to the scale-free partonlike PDF.

Qian Wu

Zhu-Fang Cui

Spain

Jorge Segovia

Parton distribution functions of ground state mesons composed of <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>c</mi></math> or <math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><mi>b</mi></math> quarks

The distribution of angular correlations between prompt charm hadrons and primary charged particles in pp collisions is sensitive to the charm-quark hadronisation process. In this letter, charm-baryon correlations are measured for the first time by studying the azimuthal-angle difference between charged particles and prompt <math altimg='si1.svg'><msubsup><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mtext>c</mtext></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math> baryons produced in pp collisions at a centre-of-mass energy of <math altimg='si2.svg'><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>13</mn></math> TeV, with the ALICE detector. <math altimg='si1.svg'><msubsup><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mtext>c</mtext></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math> baryons are reconstructed at midrapidity ( <math altimg='si5.svg'><mo stretchy='false'>|</mo><mi>y</mi><mo stretchy='false'>|</mo><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>0.5</mn></math>) in the transverse-momentum interval <math altimg='si6.svg'><mn>3</mn><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><msub><mrow><mi>p</mi></mrow><mrow><mtext>T</mtext></mrow></msub><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>16</mn></math> GeV/ <italic>c</italic>, and correlated with charged particles with <math altimg='si7.svg'><msub><mrow><mi>p</mi></mrow><mrow><mtext>T</mtext></mrow></msub><mo linebreak='goodbreak' linebreakstyle='after'>&gt;</mo><mn>0.3</mn></math> GeV/ <italic>c</italic> and pseudorapidity <math altimg='si8.svg'><mo stretchy='false'>|</mo><mi>&#951;</mi><mo stretchy='false'>|</mo><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>0.8</mn></math>. For <math altimg='si9.svg'><mn>3</mn><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><msubsup><mrow><mi>p</mi></mrow><mrow><mtext>T</mtext></mrow><mrow><msubsup><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mtext>c</mtext></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup><mo>,</mo><mtext>D</mtext></mrow></msubsup><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>5</mn></math> GeV/ <italic>c</italic>, the comparison with published measurements of D-meson and charged-particle correlations in the same collision system hints at a larger number of low-momentum particles associated with <math altimg='si1.svg'><msubsup><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mtext>c</mtext></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math>-baryon triggers than with D-meson triggers, both in the collinear and opposite directions with respect to the trigger particle. These differences can be quantified by the comparison of the properties of the near- and away-side correlation peaks, and are not reproduced by predictions of various Monte Carlo event generators, generally underpredicting the associated particle yields at <math altimg='si10.svg'><msubsup><mrow><mi>p</mi></mrow><mrow><mtext>T</mtext></mrow><mrow><mtext>assoc</mtext></mrow></msubsup><mo linebreak='goodbreak' linebreakstyle='after'>&lt;</mo><mn>1</mn></math> GeV/ <italic>c</italic>. This tension between <math altimg='si1.svg'><msubsup><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mtext>c</mtext></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math>-baryon and D-meson associated peak yields could suggest a modified fragmentation of the charm quark, or a different hadronisation process, when a charm baryon is produced in the final state.

France

S. Acharya

India

A. Agarwal

Switzerland

G. Aglieri Rinella

L. Aglietta

M. Agnello

N. Agrawal

Z. Ahammed

S. Ahmad

S.U. Ahn

Slovakia

I. Ahuja

A. Akindinov

V. Akishina

M. Al-Turany

D. Aleksandrov

B. Alessandro

H.M. Alfanda

Mexico

R. Alfaro Molina

B. Ali

A. Alici

N. Alizadehvandchali

A. Alkin

Norway

J. Alme

G. Alocco

T. Alt

A.R. Altamura

I. Altsybeev

J.R. Alvarado

M.N. Anaam

Romania

C. Andrei

United Kingdom

N. Andreou

A. Andronic

E. Andronov

V. Anguelov

F. Antinori

P. Antonioli

N. Apadula

L. Aphecetche

Studying charm hadronisation into baryons with azimuthal correlations of <math altimg='si1.svg'><msubsup><mrow><mi mathvariant='normal'>&#923;</mi></mrow><mrow><mtext>c</mtext></mrow><mrow><mo linebreak='badbreak' linebreakstyle='after'>+</mo></mrow></msubsup></math> with charged particles in pp collisions at <math altimg='si2.svg'><msqrt><mrow><mi>s</mi></mrow></msqrt><mo linebreak='goodbreak' linebreakstyle='after'>=</mo><mn>13</mn></math> TeV